Engineering College

A motor vehicle has a mass of 1.8 tonnes and its wheelbase is 3 m. The centre of gravity of the vehicle is situated in the central plane 0.9 m above the ground and 1.7 m behind the front axle. When moving on the level at 90 km/h the brakes applied and it comes to a rest in a distance of 50 m.
Calculate the normal reactions at the front and rear wheels during the braking period and the least coefficient of friction required between the tyres and the road. (Assume g = 10 m/s2)

Answers

Answer 1

Answer:

1) The normal reactions at the front wheel is 9909.375 N

The normal reactions at the rear wheel is 8090.625 N

2) The least coefficient of friction required between the tyres and the road is 0.625

Explanation:

1) The parameters given are as follows;

Speed, u = 90 km/h = 25 m/s

Distance, s it takes to come to rest = 50 m

Mass, m = 1.8 tonnes = 1,800 kg

From the equation of motion, we have;

v² - u² = 2·a·s

Where:

v = Final velocity = 0 m/s

a = acceleration

∴ 0² - 25² = 2 × a × 50

a = -6.25 m/s²

Force, F = mass, m × a = 1,800 × (-6.25) = -11,250 N

The coefficient of friction, μ, is given as follows;

$\mu =\dfrac{u^2}{2 \times g \times s} = \dfrac{25^2}{2 \times 10 \times 50} = 0.625$

Weight transfer is given as follows;

$W_{t}=\dfrac{0.625 \times 0.9}{3}\times \dfrac{6.25}{10}\times 18000 = 2109.375 \, N$

Therefore, we have for the car at rest;

Taking moment about the Center of Gravity CG;

$F_R$ × 1.3 = 1.7 × $F_F$

$F_R$ + $F_F$ = 18000

$F_R + \dfrac{1.3 }{1.7} \times F_R = 18000$

$F_R$ = 18000*17/30 = 10200 N

$F_F$ = 18000 N - 10200 N = 7800 N

Hence with the weight transfer, we have;

The normal reactions at the rear wheel $F_R$ = 10200 N - 2109.375 N = 8090.625 N

The normal reactions at the front wheel $F_F$ = 7800 N + 2109.375 N = 9909.375 N

2) The least coefficient of friction, μ, is given as follows;

$\mu = \dfrac{F}{R} = \dfrac{11250}{18000} = 0.625$

The least coefficient of friction, μ = 0.625.

Related Questions

please i want to paraphrase this paragraph please helppppppppp don't skip!!!!!!

Answers

I’m sorry but I can’t read all of it maybe you should write it in type so we can read it.

There are gauges available for checking panel flushness. TRUE OR FALSE?

Answers

Answer: true

Explanation:

because flushness means your dead so you are dead now

There are gauges available for checking panel flushness. to allow for front-to-back movement. to allow for side-to-side movement. for height adjustments. So yes it is true. Hope this helps!

the control circuit must produce an output of 1 if at least two of the conditions 1,2 and 3 are true. design the simplest circuit that can be used for this purpose.

Answers

The simplest circuit that can be used for the control circuit must produce an output of 1 if at least two of the conditions 1,2 and 3 are true is given below.

What is control circuit?

A special kind of circuit known as a control circuit is used to regulate the performance of a totally independent power circuit. Think about a water pump being driven by a 1,000 horsepower, large industrial motor. A high voltage electrical source with a 2,400 volt output is connected to the motor.

For the safety of the operator and the machinery, a control circuit is used to ensure that the motor is started and stopped safely.

The thermostat for a home's air conditioner is an illustration of a control circuit that is frequently used. The thermostat is a component of a low-voltage control circuit that manages a relay that actually activates and deactivates the power circuit to the air conditioner compressor.

See the given attachment below for the simplest circuit↓↓

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the control circuit must produce an output of 1 if at least two of the conditions 1,2 and 3 are true.

pls help me it’s due today

Answers

Answer:

C. 14.55

Explanation:

12 x 10 = 120

120 divded by 10 is 12

so now we do the left side

7 x 3 = 21 divded by 10 is 2

so now we have 14

and the remaning area is 0.55

so 14.55

what did astronaut lovell radio when the engines of apollo 8 worked so that the spacecraft could leave lunar orbit?

Answers

When the engines of Apollo 8 started so that the spacecraft could depart lunar orbit, astronaut Lovell radioed "Roger, kindly be told there is a Santa Claus."

Why was Apollo 8 such a big deal?

Apollo 8 demonstrated the capability of the tools, the astronauts, and the whole Apollo program team to launch a crewed trip to the Moon, carry out activities in lunar space, and safely return the astronauts to Earth.

How did the Apollo 8 mission turn out?

On December 21, 1968, Apollo 8 was the very first mission to send people to the Moon and back. The journey, which tested the aircraft trajectory and procedures getting there and back, was a crucial precursor to a lunar landing even though the crew did not touch down on the moon's surface.

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It is okay to speed 7-10 mph over the posted speed limit.
The police cannot write speeding tickets for that.

Answers

Answer:

it is okay depending on how u drive

If a rubber band is stretched adiabatically, its temperature increases. (a) If the rubber band is stretched isothermally, does its entropy in- (b) If the rubber band is stretched adiabatically, does the internal crease, decrease, or stay the same? Energy increase, decrease, or stay the same?

Answers

This isn’t a hard question u have to really think tho A

1. a soil-mantled hillslope with horizontal dimensions of 250 m x 250 m has a uniform slope of 0.3. at the toe of the hillslope, there is a streambank that is 2 m high. if the hydraulic conductivity of the soil is 2.4 m/hr, what infiltration rate of precipitation would be required to fully saturate the stream bank to the nearest mm/hr?

Answers

It would take approximately 1 hour for the given infiltration rate of precipitation to fully saturate the stream bank and meet the required volume.

To calculate the infiltration rate of precipitation required to fully saturate the stream bank, we need to consider the volume of water that needs to infiltrate into the soil.

The volume of water needed to fully saturate the stream bank network can be calculated as follows:

Volume = Area * Height

Area = Width * Length

= 250 m * 250 m

= 62,500 m^2

Height = Streambank height + Slope height

= 2 m + (250 m * 0.3)

= 2 m + 75 m

= 77 m

Volume = 62,500 m^2 * 77 m

= 4,812,500 m^3

Now, we can calculate the time required for this volume of water to infiltrate into the soil. The time can be calculated using Darcy's law:

Q = K * A * h / t

Where:

Q is the volume of water (4,812,500 m^3)

K is the hydraulic conductivity of the soil (2.4 m/hr)

A is the area (62,500 m^2)

h is the height of water (77 m)

t is the time (unknown)

By rearranging the equation, we can solve for t:

t = K * A * h / Q

t = 2.4 m/hr * 62,500 m^2 * 77 m / 4,812,500 m^3

Simplifying the equation, we find:

t = 1 hr

Therefore, it would take approximately 1 hour for the given infiltration rate of precipitation to fully saturate the stream bank and meet the required volume.

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Question 2
For the circuit above in question 1, what is the most negative value v_{s}v
s

can take
before the amplifier saturates? Express your answer in mV and omit
units from your answer.

Answers

The most negative value can take before the amplifier saturates. Suppose, Consider a non-ideal op amp where the output can saturate. Hence, The most negative value of is 0.5 mV

Can take before the amplifier saturates?

The most negative value v2 can take before the amplifier saturates.Suppose, Consider a non-ideal op amp where the output can saturate.The open voltage gain is2*10 4 where,According to figure,

The negative output value is

v0 = -10V

We need to calculate the most negative value of

Using given formula

v0 = -A(Vs)

Where, = output value

A = voltage gain

Put the value into the formula

-10 = -2 *10 4* Vs

vs = 10/2*10 4

Vs = 0.0005v

Vs = 0.5MV

Hence, The most negative value of is 0.5 mV.

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The most negative value can take before the amplifier saturates. Suppose, Consider a non-ideal op amp where the output can saturate. Hence, The most negative value of is 0.5 mV

Can take before the amplifier saturates?

The most negative value v2 can take before the amplifier saturates. Suppose, Consider a non-ideal op amp where the output can saturate. open voltage gain is2*10 4 where, According to figure,

The negative output value is

v0 = -10V

We need to calculate the most negative value of

Using given formula

v0 = -A(Vs)

Where, = output value

A = voltage gain

Put the value into the formula

-10 = -2 *10 4* Vs

vs = 10/2*10 4

Vs = 0.0005v

Vs = 0.5MV

Hence, The most negative value of is 0.5 mV.

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You have a Linux system that has a 1000GB SSD, which has a 90GB partition containing an ext4 filesystem mounted to the / directory and a 4GB swap partition. Currently, this Linux system is only used by a few users for storing small files; however, the department manager wants to upgrade this system and use it to run a database application that will be used by 100 users. The database application and the associated data will take up over 200GB of hard disk space. In addition, these 100 users will store their personal files on the hard disk of the system. Each user must have a maximum of 5GB of storage space. The department manager has made it very clear that this system must not exhibit any downtime as a result of hard disk errors. How much hard disk space will you require, and what partitions would you need to ensure that the system will perform as needed? Where would these partitions be mounted? What quotas would you implement? What commands would you need to run and what entries to /etc/fstab would you need to create? Justify your answers.

Answers

Given the requirements and constraints, you will need to ensure that the system has sufficient hard disk space to accommodate the database application and the user data, while also ensuring that the system remains stable and free of hard disk errors. To do this, you will need to take the following steps:

Add Hard Disk Space: You will need to add enough hard disk space to accommodate the database application and user data. Given that the database application requires over 200GB of disk space, and each user requires 5GB of disk space, you will need a minimum of 200 + (100 x 5) = 700GB of hard disk space. If you have a spare 1000GB SSD available, you can use that.Create Partitions: You will need to create two partitions on the hard disk: one for the database application and another for the user data. Given that the database application requires over 200GB of disk space, you should create a partition with at least 200GB of disk space for the database application. Given that each user requires 5GB of disk space, you should create a partition with at least 100 x 5 = 500GB of disk space for the user data.Mount Partitions: You should mount the partition containing the database application to the /var/lib/mysql directory, and the partition containing the user data to the /home directory. This will ensure that the database application and user data are stored in separate partitions and do not interfere with each other.Implement Disk Quotas: To limit each user's disk usage to 5GB, you will need to implement disk quotas for the /home partition. You can do this by using the quota command, which allows you to set disk usage limits for individual users or groups of users.Update /etc/fstab: You will need to update the /etc/fstab file to specify the partitions that you have created and the mount points for those partitions. This will ensure that the partitions are mounted automatically when the system is started.

Here is an example of what the entries in /etc/fstab might look like:

/dev/sda1 /var/lib/mysql ext4 defaults 0 0

/dev/sda2 /home ext4 defaults,usrquota 0 0

To implement the disk quotas, you will need to run the following commands:

# touch /aquota.user

# chmod 600 /aquota.user

# mount -o remount /home

# quotacheck -avugm /home

# quotaon -avug

These steps should ensure that your Linux system meets the requirements and constraints set by the department manager, while also providing a stable and efficient system for the 100 users who will be using the database application.

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During a static governor adjustment, make sure that the speed control is in ________ ?

Idle position
Curb idle position
Transition speed
Fast or wide-open throttle position

Answers

Answer:

Fast or wide-open throttle position

What current works best when the operator
encounters magnetic arc blow?

•DCEP

•ACEN

•CC

•AC

Answers

Answer:

Explanation:

One situation when alternating current would work better than direct current is if the operator is encountering magnetic arc blow.

Current works best when the operator encounters magnetic arc blow is AC

Magnetic arc blow is simply defined as the arc deflection due to the warping of the magnetic field that is produced by electric arc current.

This is caused as a result of the following;

- if the material being welded has residual magnetism at an intolerable level

- When the weld root is being made, and the welding current is direct current which indicates constant direction and maintains constant polarity (either positive or negative).

Since it is caused by DC(Direct Current) which means constant polarity , it means the opposite will be better which is AC(alternating current) because it means that electricity direction will be switching to and fro and as such the polarity will also be revered in response to this back and forth switch manner.

Thus, Current works best when the operator encounters magnetic arc blow is AC

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(a) In a group of 200 people, at least how many have names beginning with the same letter of the alphabet?
(b) How many people must be in a room to ensure that at least 8 were born on the same day of the week?
(c) If |A| = 10 and |B| = 100, how many functions from A to B are injective?
(d) If |A| = 10 and |B| = 10, how many functions from A to B are bijective?

Answers

a. Considering that everyone in the group has an equal chance of having a name that starts with a particular alphabet,

Amount of individuals with first names that begin with the same letter of the alphabet: 200/26 = 7.69

There will be at least 7 people with the same first letter.

How to solve the probability

(b) Considering that everyone has an equal chance of being born on a particular day of the week,

8*7 = 56 people must be born on the same day of the week in order for there to be at least 8 people in the room.

(c) Because every element in an injective function from A to B maps to a single distinct element in B, the total number of injective functions is equal to the number of possible assignments of an element in B to every element in A. component of A.

Therefore,

Total amount of injective operations: 62815650955529530000 (100C10*10)

(d) By fixing the elements of A and assigning a different element from B to each element in A, the number of bijective functions from A to B may be determined because the size of both sets A and B is identical (ensuring that each element in B is mapped to each element in A and vice versa). This is the same as the number of ways the element in B can be configured.

Therefore,

10! = 3628800 is the total number of bijective functions.

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1. You use
switches when you
have two switches controlling one or more
lights.
single pole
4-way
2-way
3-way

Answers

4-ways tell me if I’m wrong

The load is 200g and is 5' away from
the fulcrum, what is the mechanical
advantage and how many newtons of
force needed to lift the load?

Answers

Answer:

In 1st class levers, the fulcrum is always between the effort force and the load. It may or may not provide a mechanical advantage, depending on the location.

Explanation:

.If aligned and continuous carbon fibers with a diameter of 6.90 micron are embedded within an epoxy, such that the bond strength across the fiber-epoxy interface is 17 MPa, and the shear yield strength of the epoxy is 68 MPa, compute the minimum fiber length, in millimeters, to guarantee that the fibers are conveying an optimum fraction of force that is applied to the composite. The tensile strength of these carbon fibers is 3960 MPa.

Answers

Answer:

the required minimum fiber length is 0.80365 mm

Explanation:

Given the data in the question;

Diameter D = 6.90 microns = 6.90 × 10⁻⁶ m

Bond strength ζ = 17 MPa

Shear yield strength ζ$_y$ = 68 Mpa

tensile strength of carbon fibers $6t_{fiber$ = 3960 MPa.

To determine the minimum fiber length we make use of the following relation;

L = ($6t_{fiber$ × D) / 2ζ

we substitute our given values into the equation;

L = ( 3960 × 6.90 × 10⁻⁶) / (2 × 17 )

L = 0.027324 / 34

L = 0.000803647 m

L = 0.000803647 × (1000) mm

L = 0.80365 mm

Therefore, the required minimum fiber length is 0.80365 mm

A batch production operation has a machine setup time of 3.0 hr and a processing time of 1.60 min per cycle. Two parts are produced each cycle. No tool handling time is included in the cycle. Part handling time each cycle is 45 sec. It consists of the worker obtaining two starting work units from a parts tray, loading them into the machine, and then after processing, unloading the completed units and placing them into the same tray. Each tray holds 24 work units. When all of the starting work units have been replaced with completed units, the tray of completed parts is moved aside and a new tray of starting parts is moved into position at the machine. This irregular work element takes 3.0 min. Batch quantity is 2,400 units.
Determine :
(a) average cycle time,
(b) time to complete the batch,and
(c) average production rate.

Answers

The average cycle time is 94.85 seconds. The time required to complete the batch is 227,640 seconds, or approximately 63.23 hours

How to calculate the Average cycle time and average production rate

(a) Average Cycle Time:

The cycle time can be calculated as the sum of the setup time, processing time per cycle, and part handling time per cycle, divided by the number of parts produced per cycle.

Cycle Time = (Setup Time + Processing Time + Part Handling Time) / Number of Parts Produced

Setup time = 3.0 hours = 180 minutes

Processing time per cycle = 1.60 minutes x 2 = 3.20 minutes

Part handling time per cycle = 45 seconds x 2 = 1.50 minutes

Irregular work element time = 3.0 minutes

Cycle Time = (180 + 3.20 + 1.50 + 3.0) / 2 = 94.85 seconds

Therefore, the average cycle time is 94.85 seconds.

(b) Time to Complete the Batch:

To calculate the time required to complete the batch, we need to multiply the batch quantity by the cycle time.

Time to Complete Batch = Batch Quantity x Cycle Time

Time to Complete Batch = 2,400 x 94.85 seconds = 227,640 seconds

Therefore, the time required to complete the batch is 227,640 seconds, or approximately 63.23 hours.

The average production rate can be calculated as the batch quantity divided by the time to complete the batch.

Average Production Rate = Batch Quantity / Time to Complete Batch

Average Production Rate = 2,400 / 227,640 seconds = 0.0105 units per second

Therefore, the average production rate is 0.0105 units per second.

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Determine numerical values for each of the three mesh currents as labeled in
the circuit diagram of Fig. 4.58.

Answers

The numerical values for the mesh currents that we have in the question are given as:

1i = 0.9892 = 0.9892 amperei2 = 0.1501 amperei3 = 0.1570 ampere

How to solve for the values of the mesh current

We first have to write the KVL

2 - 1(i₁ - i₂) + 3 - 5(i₁ - i₃) = 0

We have to expand the equation that we have above

2 - i₁ + i₂ + 3 - 5i₁ + 5i₃ = 0

take like terms

-i₁ - 5i₁ i₂ + 5i₃ = 5

= 6i₁ - i₂ - 5i₃ = 5

-1(i₂ - i₁) - 6 i₂ - 9(i₃ - i2) = 0

after expanding we would have

i₁ - 16i₂ + 9i₃ = 0------- equation 2

-5 (i3 - i1) - 3 - 9(i3 - i2) - 7i3 = 0

5i1 + 9i2 - 2i3 = 3 ------ equation 3

From the equations that we have in 1, 2 and 3, we would solve the system of equations to get

1i = 0.9892 = 0.9892 ampere

i2 = 0.1501 ampere

i3 = 0.1570 ampere

These are the mesh current that are in the labeled diagram.

Answers

If a steel containing 1.13 wt% C is cooled relatively slowly to room temperature, the expected weight fraction of pearlite in the as-cooled microstructure can be determined using the lever rule and the iron-carbon phase diagram.

The lever rule is a mathematical tool used in metallurgy to determine the proportions of different phases in a two-phase alloy. The iron-carbon phase diagram represents the phase transformations and stable phases that occur in iron-carbon alloys as a function of temperature and composition. In this case, the steel has a composition of 1.13 wt% carbon, which falls within the eutectoid region of the iron-carbon phase diagram.

When cooled slowly to room temperature, this steel will transform into a mixture of pearlite and proeutectoid cementite. To calculate the weight fraction of pearlite, the lever rule can be applied using the carbon content of the alloy (1.13 wt% C), the eutectoid composition (0.76 wt% C), and the proeutectoid cementite composition (6.67 wt% C). According to the lever rule, the weight fraction of pearlite in this steel would be approximately 0.85 or 85%.

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describe an engineering advance that has led to greater knowledge about the solar system

Answers

development of the space shuttle to allow humans to explore the moon

Answer:

Space Rovers

Explanation:

The engineering advancement of the invention space rovers has changed space exploration tremendously. The first space rover ever to go out onto another planet was made by NASA and put on mars to learn more about the red planet and see if there where any plausible signs of past or maybe even present life. This mission was incredibly successful and for the first time in space exploration history, there was a spacecraft that you could move around that could with do the conditions of the planet for weeks, months, sometimes years at a time, moving around taking pictures and constantly collecting data. This was revolutionary for scientists, this way they could get copious amounts of information just on rover and not having to send multiple crafts only to die in the first few hours but sending back a relative amount of information. With rovers you can have them collect samples and bring the back to earth, not something that could’ve been done without a human, until rovers. They have completely changed and improved collecting data from other planets and have been one of the most revolutionary inventions when it comes to space exploration.

This is what I put for the answer, hope it helps in some way.

PLEASE FILL IN BLANK WITH CORRECT ANSWER
1. We cannot solve _____ by simplex.
2. In any integer basic feasible solution of the _____, the number of positive variables is equal to half the number of functional constraints.
3. A discrete dynamic programming problem can be represented by a _____.
4. A tree is a special case of a _______.

Answers

1. We cannot solve nonlinear programming problems by simplex.The simplex method is utilized for linear programming problems only. The LP problems have linear constraints and a linear objective function. The nonlinear programming problems cannot be solved by the simplex method.

We have to use the other methods for these kinds of issues.2. In any integer basic feasible solution of the transportation problem, the number of positive variables is equal to half the number of functional constraints. It is feasible to use a solution that is restricted to whole numbers for transportation problems. We've got a few formulas that can help us figure out the answers.3. A discrete dynamic programming problem can be represented by a tree. To solve a dynamic programming problem, we typically use a graph structure known as a decision tree. The nodes of a decision tree represent decision points, and the arcs represent the choices available at each decision point.4. A tree is a special case of a graph. Trees are a special kind of graph, so it makes sense that they're also used to represent decision trees. Trees are graphs with nodes linked together in a particular manner. There is a parent-child relationship between the nodes of a tree, which means that each node has only one parent and zero or more children. Trees have no cycles, which means that there is no way to traverse the tree from a node to itself without first traversing a node that is not a descendant.

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Which one of the following answer options are your employers responsibility

Answers

Where are your answer options?

Answer:

Implement a hazard communication program

Explanation: i took the quiz

Which contemporary jazz artist was one of the first to use a synthesizer in their recording

Answers

Answer:

In this era, Sun Ra was among the first of any musicians to make extensive and pioneering use of synthesizers and other various electronic keyboards; he was given a prototype Minimoog by its inventor, Robert Moog.

Explanation:

The three main principles in engineering design are:

Answers

The three main principles in engineering design are: strategic balance, top management approach and team work.

What does principles in engineering design means?

The principles are fundamental concepts that engineers use to develop effective solutions to complex problems. These principles are based on scientific and mathematical principles as well as practical considerations related to the materials, technologies and resources available to the engineer.

The engineering design process involves several stages, including problem identification, research, concept development, prototyping and testing. Throughout each stage, engineers apply various principles to ensure that their designs meet the needs and requirements of the intended users.

Answers

Yes, I can help you create a Network Diagram and Chart based on the given information.

Creating a Network Diagram and Chart involves analyzing the dependencies between different activities in a project schedule to determine the critical path and identify the total float for each activity.

In the first step, the forward pass is calculated to determine the early start and early finish dates for each activity. Starting with activity A having an early start on day 1, the forward pass calculates the earliest possible start and finish dates for each subsequent activity based on their dependencies and durations.

In the second step, the backward pass is calculated to determine the late start and late finish dates for each activity. The late finish date for activity D is given as day 22, and by working backwards from that point, we can determine the latest possible start and finish dates for each preceding activity.

Finally, in the third step, the total float for each activity is calculated. Total float represents the amount of time an activity can be delayed without affecting the project's overall duration. It is calculated by finding the difference between the late start and early start dates (or late finish and early finish dates) for each activity. Activities with zero total float are on the critical path, meaning any delay in their completion will directly impact the project's duration.

By following these steps, we can create a Network Diagram and Chart that visually represents the project schedule, identifies the critical path, and provides information about the total float for each activity.

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If the drag on one side of a flat plate parallel to the flow is D when the upstream velocity is U and the boundary layer How is laminar, what will be the drag be when the upstream velocity is 2U and U/2? Express your answer as a function of density p. length of the plate l. width of the plate b, kinematic viscosity v. and U.

Answers

To determine the drag on a flat plate under different conditions, we need to consider the drag coefficient and the reference area. The drag coefficient depends on the flow regime (laminar or turbulent) and can be approximated using different correlations.

Drag at U: 0.664 * ρ * U^2 * l^2

Drag at 2U: 2.656 * ρ * U^2 * l^2

Drag at U/2: 0.166 * ρ * U^2 * l^2

For a flat plate with a laminar boundary layer, we can use the following relationships:

Drag coefficient for laminar flow on a flat plate:

Cd = (1.328 / sqrt(Re)) * (2l/b)

where Re is the Reynolds number, given by Re = (ρU l) / μ, with ρ being the density, U the velocity, l the length of the plate, and μ the dynamic viscosity.

Reference area:

The reference area, denoted as A, is the projected area of the plate perpendicular to the flow. For a flat plate, A = l * b.

Now, we can calculate the drag for different velocities:

Upstream velocity U:

Drag = 0.5 * Cd * ρ * U^2 * A

= 0.5 * [(1.328 / sqrt(Re)) * (2l/b)] * ρ * U^2 * l * b

= 0.664 * ρ * U^2 * l^2

Upstream velocity 2U:

Drag = 0.5 * Cd * ρ * (2U)^2 * A

= 0.5 * [(1.328 / sqrt(Re))] * ρ * (2U)^2 * l * b

= 2.656 * ρ * U^2 * l^2

Upstream velocity U/2:

Drag = 0.5 * Cd * ρ * (U/2)^2 * A

= 0.5 * [(1.328 / sqrt(Re))] * ρ * (U/2)^2 * l * b

= 0.166 * ρ * U^2 * l^2

Therefore, the drag on the flat plate when the upstream velocity is U, 2U, and U/2 can be expressed as:

Drag at U: 0.664 * ρ * U^2 * l^2

Drag at 2U: 2.656 * ρ * U^2 * l^2

Drag at U/2: 0.166 * ρ * U^2 * l^2

Please note that these calculations assume laminar flow and neglect any other external factors that may affect the drag on the plate.

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when replacing a battery: technician a says the negative battery cable should be connected first, then connect the positive battery cable. technician b says the negative battery cable should be disconnected first, then disconnect the positive battery cable. who is correct?

Answers

Technician A is correct. Connect the negative battery cable first, then connect the positive cable for battery replacement.

Technician A is correct. When replacing a battery, it is recommended to connect the negative battery cable first and then connect the positive battery cable.

This sequence is important for safety reasons. By connecting the negative cable first, any accidental contact between the positive cable and metal surfaces can be minimized, reducing the risk of electrical sparks or short circuits. Similarly, when removing the battery, it is advised to disconnect the negative cable first and then disconnect the positive cable.

This order prevents any unintentional electrical connections while handling the battery. Following this procedure ensures safer battery replacement and reduces the chances of electrical hazards or damage to the vehicle's electrical system.

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A car makes a hissing noise each time the A/C system and engine are turned off. Technician A says that the noise is caused by a refrigerant leak. Technician B says that the noise is caused by equalization of system pressures. Who is correct?

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Answer:

It's equalization of the system

Explanation: If there was a leak it would likely leak all the time even if the car was turned off. Plus, a system leak bad enough to hear would drain the system of refrigerant very quickly and would no longer cool.

Part C 1 pts What is the output of the following code? (check all that apply) int option = 2; switch (option) { case 1: System.out.println("You entered 1"); case 2: System.out.println("You entered 2"); case 3: System.out.println("You entered 3"); default: System.out.println("You entered an invalid option"); } You entered 3 You entered an invalid option You entered 1 You entered 2

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The correct outputs Code are "You entered 2", "You entered 3", and "You entered an invalid option".

The output of the given code will be:
You entered 2
You entered 3
You entered an invalid option

This is because the switch statement is based on the value of the variable 'option', which is initialized as 2. So, it will execute the code block under the case 2, which is to print "You entered 2". However, there are no break statements after each case, so it will continue to execute the code blocks under the subsequent cases until it reaches a break statement or the end of the switch statement. Therefore, it will also print "You entered 3".

Since there is no case for option equal to 4, the default code block will execute and print "You entered an invalid option".

So, the correct outputs are "You entered 2", "You entered 3", and "You entered an invalid option".

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An engineer wants to design a knee replacement.Identify one criterion the design should meet.

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What details do u want exactly??

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