At the gym, a man pulls a bar on a machine that works the muscles of the upper back. It takes him 0. 5 seconds to raise 30


kilograms of weights a vertical distance of 0. 5 meters.


Which of these exerts the same power output? (Estimate g as 10 m/s2. )



A) lifting 25 kilograms a distance of 2. 4 meters in 2. 0 seconds



B) lifting 45 kilograms a distance of 2. 4 meters in 3. 0 seconds


C) leg pressing 45 kilograms a distance of 0. 5 meters in 0. 5 seconds.


D) bench pressing 30 ligrograms a distance of 0. 5 meter in 1. 5 seconds.


Pleaseeeeeee help me

To derive the differential equation for the volume of a spherical raindrop as a function of time, we need to consider the relationship between the rate of evaporation and the surface area of the raindrop.

First, let's start with the formula for the volume of a sphere:

V = (4/3)πr^3

where V is the volume and r is the radius of the raindrop.

The surface area of a sphere is given by:

A = 4πr^2

where A is the surface area.

Since the rate of evaporation is proportional to the surface area, we can write:

dV/dt = -kA

where dV/dt represents the rate of change of volume with respect to time, and k is a proportionality constant.

Now, substitute the equation for the surface area into the equation for the rate of change of volume:

dV/dt = -k(4πr^2)

dV/dt = -k(4π(3V/4π)^(2/3))

Simplifying further:

dV/dt = -k(4π(3^(2/3))V^(2/3))

Finally, dV/dt = -kV^(2/3)

Therefore, the differential equation for the volume of the raindrop as a function of time is dV/dt = -kV^(2/3).

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Answer:

-10C= Solid

10C= Liquid

50C= Liquid

90C= Liquid

110C= Gas

120C= Gas

Explanation:

Below 0 degree C (Celsius), water is frozen means it is in the form of ice. After 0 degree, once we keep it in room temperature, the ice starts becoming liquid (water), and once we heat water, after 100 degree C (Celsius) water starts boiling and thus starts entering gaseous state.

True. The heat flux is independently of x for only one steady-state conduction in some kind of a planar wall without heat creation.

The thermal energy that is emitted over a concrete surface is known as heat flux, and its unit is W/m2. The equation dotq = fracQA can be used to determine heat flow.

The source of energy flux at the surface of a hard object is frequently a combination of convective and contributions. By allowing this heat to pass throughout a heat flux sensor, conductive and convective heat fluxes can be monitored. Heat flux monitors are either embedded in or installed on the surface of an solid item.

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The acceleration of the aircraft will be 2.571 m/sec².Acceleration is denoted by a.

Acceleration is defined as the rate of change of the velocity of the body. Its unit is m/sec².It is a vector quantity. It requires both magnitudes as well as direction to define.

Given data;

Initial velocity,u= 0 m/sec

Final velocity,v=72 m/sec

Time period,t= 28 sec

Acceleeration,a=?

The acceleration of the aircraft is;

\(\rm a = \frac{v-u}{t} \\\\\ a= \frac{72-0}{28} \\\\\ a=2.571 \ m/sec^2\)

​

Hence, the acceleration of the aircraft will be 2.571 m/sec.

​

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Explanation:

One of the interesting things about projectile motion is that the horizontal motion is independent of the vertical motion. Recall that in freefall, an object continually experiences a downward acceleration of 9.80ms2 but has no horizontal acceleration.

Answer:

Bottle opener works on a fulcrum.

Explanation:

A bottle opener is a second-class lever because the pivot point is at one end of the opener and the load is in the middle.

The final velocity of the object after 5.00 s is 12.5 m/s (east).

The given information are:

Initial velocity, u = 3.50 m/s

Constant acceleration, a = 1.80 m/s²Time taken, t = 5.00 s

Using the kinematic equation,v = u + at

where,v = final velocity

u = initial velocity

a = acceleration

t = time

Substituting the given values,

v = u + atv = 3.50 m/s + (1.80 m/s²)(5.00 s)v

= 3.50 m/s + 9.00 m/sv

= 12.5 m/s

The final velocity of the object after 5.00 s is 12.5 m/s (east).

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Answer:

I) 420000J

ii)

Explanation:

(I) so you can use the formula for quantity of heat then substitute the values given

formula-Q=mc∆9

Trusses are structures made up of interconnected triangles that are used to support loads. The members of the truss can either be in tension or compression, depending on the orientation of the load.

To determine the force in each member of the truss, you first need to analyze the forces acting on the entire structure. This involves drawing a free body diagram of the truss and applying the principles of statics to calculate the forces acting on each member.

Once you have determined the external forces acting on the truss, you can use the method of joints or the method of sections to analyze the internal forces in each member. In summary, determining the force in each member of a truss is a complex process that involves analyzing the external forces acting on the structure, using the method of joints or the method of sections to analyze the internal forces in each member, and determining whether the members are in tension or compression.

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Aluminum is used on spacecraft for radiation shielding instead of lead due to its lighter weight and better mechanical properties.

When it comes to radiation shielding in spacecraft, weight is a crucial factor as it affects the overall mass of the vehicle. Aluminum offers a significant advantage over lead in terms of weight. Aluminum has a lower density compared to lead, which means that it can provide effective shielding while adding less weight to the spacecraft. This is especially important for space missions where every kilogram of weight saved can have a significant impact on the mission's cost and performance.

Additionally, aluminum possesses favorable mechanical properties that make it suitable for spacecraft applications. It is strong, durable, and exhibits good resistance to corrosion. These properties are essential for withstanding the harsh conditions of space and ensuring the structural integrity of the spacecraft.

Another material that could be a good choice for spacecraft shielding is polyethylene. Polyethylene is a lightweight plastic material that has excellent radiation shielding properties. It is commonly used in nuclear power plants and medical facilities for radiation protection. Polyethylene has high hydrogen content, which makes it effective at absorbing and attenuating ionizing radiation. Its lightweight nature and ease of fabrication make it an attractive option for spacecraft shielding, providing a good balance between radiation protection and weight efficiency.

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The voltage drop across the inductor (L) is 29.53 V.

In a series circuit with resistance R = 20 ohms, inductance L = 20 mH, and an AC supply of 60 V with frequency f = 100 Hz, the voltage drop across the inductor (V_L) can be calculated using the formula:

V_L = 2 * π * f * L * I

First, we need to find the impedance (Z) of the circuit, which is given by the formula:

Z = √(R² + (2 * π * f * L)²)

Plugging in the given values:

Z = √(20² + (2 * π * 100 * 0.02)²) ≈ 25.49 ohms

Next, we need to find the current (I) in the circuit, using Ohm's law:

I = V / Z

I = 60 V / 25.49 ohms ≈ 2.35 A

Now we can find the voltage drop across the inductor (V_L):

V_L = 2 * π * 100 Hz * 0.02 H * 2.35 A ≈ 29.53 V

Therefore, the voltage drop is approximately 29.53 V.

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Answer:

When we burn wood we are releasing solar energy, in the form of heat, that has been stored in the wood as chemical energy. The process of photosynthesis converted solar energy, water and carbon dioxide into oxygen and the organic molecules that form the wood, half the weight of which is carbon.

Explanation:

1) The number of photons in each beam is what determines the amount of energy each beam carries. A beam of red light contains more photons than a beam of blue light, but each photon in the blue beam carries more energy than each photon in the red beam. Therefore, the two beams can carry the same amount of energy despite having different energies per photon.

2) Reflecting telescopes have two advantages over refractors. They are cheaper to manufacture, and they do not suffer from chromatic aberration.

3) Refraction is the bending of light as it passes from one medium to another. Refraction occurs because light waves travel at different speeds through different materials. The amount of refraction depends on the angle at which the light passes through the medium.

4) The image of a star is larger in the focal plane of the larger telescope. This is because the larger telescope collects more light than the smaller telescope, which means that the image is brighter and has a higher signal-to-noise ratio.

5) Quantum efficiency is a measure of how efficiently a detector converts incoming photons into electrical signals. A higher quantum efficiency means that more of the incoming

photons are detected, which makes it easier to detect faint astronomical objects.

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1) The number of photons in each beam is what determines the amount of energy each beam carries.

2) Reflecting telescopes have two advantages over refractors.

3) Refraction is the bending of light as it passes from one medium to another.

4) The image of a star is larger in the focal plane of the larger telescope.

5) Quantum efficiency is a measure of how efficiently a detector converts incoming photons into electrical signals.

1) The number of photons in each beam is what determines the amount of energy each beam carries. A beam of red light contains more photons than a beam of blue light, but each photon in the blue beam carries more energy than each photon in the red beam. Therefore, the two beams can carry the same amount of energy despite having different energies per photon.

2) Reflecting telescopes have two advantages over refractors. They are cheaper to manufacture, and they do not suffer from chromatic aberration.

3) Refraction is the bending of light as it passes from one medium to another. Refraction occurs because light waves travel at different speeds through different materials. The amount of refraction depends on the angle at which the light passes through the medium.

4) The image of a star is larger in the focal plane of the larger telescope. This is because the larger telescope collects more light than the smaller telescope, which means that the image is brighter and has a higher signal-to-noise ratio.

5) Quantum efficiency is a measure of how efficiently a detector converts incoming photons into electrical signals. A higher quantum efficiency means that more of the incoming

photons are detected, which makes it easier to detect faint astronomical objects.

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Mass and Distance are the factors that determine the strength of the gravitational force between two objects.

Newton's Law of Gravitation:

According to Newton's law of universal gravitation, the gravitational force between two objects is inversely equal to their combined mass, divided by the square of the distance between the objects. Or more simply:

                            \(F=\frac{GMm}{r^{2} }\)

Where G is Newton's gravitational constant, M and m are the masses, and r is the distance between them. You can use this law to work out how much gravity is on an object.

The first factor that influences how much gravity acts on each of the items is their mass. The gravitational pull one object has on the other increases with mass. Simply said, gravity exerts more force on an item the more mass it has.

The distance between the two items is the second element that influences how much gravity is exerted on each object. The gravitational pull that one object has on the other decreases as the distance between them increases. This implies that gravity exerts more force on an object the closer it is to another.

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The maximum power generated by a HAWT with a rotor diameter of 200 m and an average wind speed of 18 miles/hour.                                                                                                                                                                                    

Formula P = 0.5 x density x area x velocity^3, where P is power, density is the density of air, area is the area of the rotor, and velocity is the wind speed. Substituting the given values, we get P = 0.5 x 1.2 x π x (100)^2 x (18 x 0.447)^3 = 2871868.8 kW.

The torque at maximum efficiency can be calculated using the formula T = P / (2 x π x rpm). Substituting the values, we get T = 2871868.8 / (2 x π x 20) = 22863.6 Nm.

The maximum power generated by a HAWT can be calculated using the power coefficient (Cp=0.593), air density (1.2 kg/m³), rotor diameter (200 m), and wind speed (18 miles/hour or 8.05 m/s) through the formula: P = 0.5 * Cp * density * Area * wind speed³.

For a rotor diameter of 200 m, the swept area (Area) is π * (diameter/2)² = 31,416 m². Plugging in the values, we get P = 0.5 * 0.593 * 1.2 * 31,416 * 8.05³ = 15,253,497 W or approximately 15,253 kW.

For maximum efficiency, the torque (T) can be calculated using the formula: T = P / (2π * RPM / 60). With a rotational speed of 20 RPM, T = 15,253,497 / (2π * 20 / 60) = 7,274,298 Nm.                                                                                  

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Answer:

b : 60m

Explanation:

when a plane mirror is placed horizontally on a level ground at a distance of 60m from the top of tower as shown in figure. a/c to question, The top of tower and its image in the mirror subtend an angle of 90° at the eyes. so, angle made by top of tower and horizontal line is 45° as

An lc circuit is built with a 40 mh inductor and an 12.0 pf capacitor. The capacitor voltage has its maximum value of 50 v at t=0s. The inductor current at t=0s is 0A.

An LC circuit is a type of resonant circuit that consists of an inductor (L) and a capacitor (C) connected in parallel. The circuit can store energy oscillating between the inductor and capacitor. At t=0s, the capacitor voltage has its maximum value of 50V, which means that the current through the capacitor is zero and the current through the inductor is also zero.

This is because at t=0s, the energy stored in the capacitor is at its maximum and there is no current flowing through the circuit. As time passes, the capacitor discharges and the current starts flowing through the inductor, which in turn stores energy in the magnetic field. The inductor current will reach its maximum value when the capacitor voltage reaches zero, at which point the energy will be stored in the magnetic field of the inductor. Therefore, at t=0s, the inductor current is 0A.

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Answer:

mass 3.67 kg, density 600 kg/m3) is fitted

with lead (density 1.14 * 10^4 kg/m3) so that it floats in water with

0.900 of its volume submerged. Find the lead mass if the lead is fitted

to the block’s (a) top and (b) bottom.

Answer:

86400 seconds is equal to 1 day.

Explanation:

Answer:

Its C

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Answer:

Six

Explanation:

Assuming she can only have ONE flavor in her cone

  2 cone types   *    3 flavors   =   6 combos

Answer:

sound Requires a medium in order to travel.

Answer:

medium

Explanation:

this is because sound waves need particles to transfer energy from one point to another

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Answer:

The combination of cells in which the negative terminal of a first cell is connected with the positive terminal of second cell and the negative terminal of a second cell is connected to the positive terminal of a third cell and so on is known as series combination of cells.

Explanation:

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Answer:

Battery.

hope it helps!

The force F1 is equal and opposite to the downward force thus, F1 is equal to 60 N. The force F2 is inclined to 30 ° from leftward force and it is equal to 38.97 N in magnitude.

Force is an external agent acting on a body to deform it or to change its state of motion or rest. Force is a vector quantity and it is characterised by its magnitude and direction.

If two forces acting on a body from the same directions, then the net force will be the sum of these two forces. If they are acting from opposite directions, they will cancel each other in magnitude.

The force F1 is equal and opposite to the force acting downward. Thus its magnitude is 60 N. The force F2 is inclined to 30 ° from horizontal direction.

F2 = 45 cos 30 = 38.9 N.

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Answer:

On Bode's advice, Herschel named his newly discovered planet after: the Greek god Uranus.

Explanation:

Herschel named his newly discovered planet Uranus on Bode's advice for a couple of reasons:

Mythological Naming Convention: During that time, it was a common practice to name celestial objects after mythological figures, particularly gods from Greek and Roman mythology. Bode suggested following this convention and recommended that Herschel choose a name from Greek mythology for the newly discovered planet.

Connection to the Sky: Uranus was chosen as the name for the planet because it was the name of the Greek god of the sky. Given that Herschel had discovered a celestial object in the sky, naming it after the god associated with the sky seemed fitting.

By naming the planet Uranus, Herschel paid homage to the mythological tradition of naming celestial bodies while also establishing a connection between his discovery and the vastness of the sky.

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Answer:

I think it is 50 j, I am not sure and also please let me know if I am wrong.

Answer: hey

Explanation:

Answer:

Cannot be determined from the given information

Explanation:

Given the following data;

Velocity = 24 m/s

Period = 3 seconds

To find the amplitude of the wave;

Mathematically, the amplitude of a wave is given by the formula;

x = Asin(ωt + ϕ)

Where;

x is displacement of the wave measured in meters.

A is the amplitude.

ω is the angular frequency measured in rad/s.

t is the time period measured in seconds.

ϕ is the phase angle.

Hence, the information provided in this exercise isn't sufficient to find the amplitude of the waveform.

However, the given parameters can be used to calculate the frequency and wavelength of the wave.