Kevin drops a pile of roof shingles from the roof 8.52 meters above the ground.
Determine the time it takes for the shingles to reach the ground?

When a ball is at a particular height it possess potential energy which is given as,

The potential energy is converted into kinetic energy of the ball. According to conservation of energy,

which can be further given as,

Substitute the known values,

Thus, the kinetic energy of the ball is 0.140 J.

Answer:

Answer: It allows people to rapidly heat items

Hope this helps!

Explanation:

Answer: B

Explanation:

A microwave cooks, thaws, and melts food at a fraction of the time.

The mass of an atom is less than the sum of the masses of its component protons, neutrons and electrons. The mass defect is 0.0423 amu. The correct option is B.

The mass defect is equal to the mass lost as an equivalent amount of energy during the formation of a given nucleus from the component nucleons.

Δm = M°- M

Δm = Mass defect

M° = Expected total mass

M = Experimentally determined mass

Here 'Li' has 3 protons and 4 neutrons.

The mass of proton = 3 × 1.0073 = 3.0219 amu

The mass of neutron = 4 × 1.0087 = 4.0348 amu

The sum of masses of protons and neutrons = 7.0567

Mass defect = 7.0567 - 7.0144 = 0.0423 amu

Thus the correct option is B.

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According to the question the speed of the skater's hands is 528 m/min.

To calculate the speed of the skater's hands, we can use the formula:

Speed = Circumference * Revolutions per minute

Given that the skater's hands are 140 cm apart and she spins at 120 rpm, we need to calculate the circumference of the circle formed by her hands.

The circumference of a circle is given by the formula:

Circumference = 2 * π * radius.

In this case, the radius is half the distance between the skater's hands, which is 140 cm / 2 = 70 cm.

Converting the radius to meters, we have 70 cm = 0.7 m.

Now we can calculate the circumference:

Circumference = 2 * π * 0.7 m = 4.4 m (rounded to one decimal place).

Finally, we can calculate the speed of the skater's hands:

Speed = Circumference * Revolutions per minute

     = 4.4 m * 120 rpm

     = 528 m/min.

Therefore, the speed of the skater's hands is 528 m/min.

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The force experienced will be 8E-15 N.

A thin circular sheet of glass with a diameter of 7 meters has been rubbed with a cloth on one of its surfaces, resulting in a uniform charge.

A chloride ion, consisting of a chlorine atom which has gained an extra electron, passes near the glass sheet. When the chloride ion is 0.8 mm away from the center of the sheet, it experiences an electric force of 8E-15 N, directed towards the glass sheet. Using the value 8.85e-12 C2/(N·m2), this force can be calculated as follows:

F = 8.85e-12 x (Q1 x Q2) / d2

Where Q1 and Q2 are the charge of the chloride ion and the glass sheet, respectively, and d is the distance between them (0.8 mm).

Therefore, the force experienced by the chloride ion is 8E-15 N, as expected.

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Answer:

True

Explanation:

Answer:TRUE

Explanation:

Answer:

The height or the mass

Explanation:

The one variable that can change the potential energy of a box on the floor is either the height or the mass of the box.

Potential energy is the energy due to the position of a body.

Mathematically;

  Potential energy  = mass x acceleration due to gravity x height

Therefore, if the mass of the box is changed, the potential energy changes also.

If the position of the box is changed by raising it up, the potential energy changes

Answer:

Explanation:

Using the principle of conservation of energy, the potential energy is converted to kinetic energy, assuming any losses.

Kinetic energy is given by ½mv²

Potential energy is given by mgh

Where m is the mass, v is the velocity, g is acceleration due to gravity and h is the height.

Equating kinetic energy to be equal to potential energy then

½mv²=mgh

V

Making v the subject of the formula

v=√(2gh)

Substituting 9.81 m/s² for g and 20 m for h then

v=√(2*9.81*20)=19.799 m/s

Rounding off, v is approximately 20 m/s

Answer:

19.8 m/s

Explanation:

During the motion of a pemdulum bob, it casually converts kinetic energy to potential energy and vice versa.

A pendulum bob reaches its maximum speed at a position closest to its equilibrium position and has its lowest when it is farthest from the equilibrium position.

The maximum speed of a pendulum bob based on the mass involved and the maximum displacement from the equilibrium position is obtained from

Maximum kinetic energy = Maximum potential energy

Maximum potential energy occurs at the farthest point from equilibrium, that is,

P.E(max) = mgh

Maximum kinetic energy = ½mv²

½mv² = mgh

v = √2gh

g = acceleration due to gravity = 9.8 m/s²

h = farthest height from equilibrium position = 20 m

v = √(2×9.8×20) = 19.8 m/s

Hope this Helps!!!

Answer:

the correct one is 3

Explanation:

The magnetic force is described by the expression

         F = q v x B

The bold indicate vectors, q is the charge, v the velocity and B the magnetic induction

This expression can be written in scalar form

        F = q v B sin θ

where θ is the angle between velocity and induction.

The direction of the force is perpendicular to the vectors.

When revising this expression the force depends on the electric charge, the speed of the particle and the induction of the magnetic field

therefore, checking the possible answers, the correct one is 3

The work done on the ball can be calculated using work-energy theorem, the work done on an object is equal to the change in its kinetic energy.

In this case, the ball's kinetic energy (KE) is changed from 20 J to 35 J. To find the work done, simply subtract the initial KE from the final KE:
Work Done = Final KE - Initial KE
Work Done = 35 J - 20 J
Work Done = 15 J
So, 15 joules of work is done on the ball to change its kinetic energy from 20 J to 35 J.

The energy that a body has because it is in motion is known as kinetic energy. Particles in solids are packed very firmly and closely together. Inside the solid, they are not at liberty to move. Only when energy is given to them, such as when the solid is heated, can they oscillate around their mean position. Particles' kinetic energy is caused by their velocity. Even if the particles move, their velocity will be very, very modest if they don't move at all. Therefore, there will be very little kinetic energy.

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A block of mass m oscillates on a With a period of T = 2.0 s, a block of mass m oscillates on a horizontal spring. The new period will be (D) 2.8 s if a second identical block is adhered on top of the first block.

When a second identical block is glued to the top of the first block, the new period of the oscillation will be affected. The period of an oscillating mass-spring system depends on the mass and the spring constant.

In this case, by adding the second block, the total mass of the system becomes 2m (since both blocks are identical). The spring constant, however, remains the same since the same spring is used.

The period of oscillation (T) is inversely proportional to the square root of the total mass (\(m_{\text{total}}\)) according to the formula \(T = 2\pi\sqrt{\frac{m_{\text{total}}}{k}}\), where k is the spring constant.

Therefore, the new period (\(T_{\text{new}}\)) can be calculated as follows:

\(T_{\text{new}} = 2\pi\sqrt{\frac{{2m}}{{k}}} = \sqrt{2} \cdot (2\pi\sqrt{\frac{{m}}{{k}}})\)

As we can see, the new period is √2 times the original period. Therefore, the new period will be:

\(T_{\text{new}}\) = √2 * T = √2 * 2.0 s ≈ 2.8 s

Therefore, the answer is D. 2.8 s.

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Answer:

Explanation:

To determine the velocity of the balloon, we can use the formula for the magnetic force on a charged particle moving in a magnetic field:

F = qvB

Where:

F is the magnetic force,

q is the charge,

v is the velocity of the balloon, and

B is the magnetic field strength.

Given:

F = -8.11 x 10^-10 N (West)

q = -0.973 μC = -0.973 x 10^-6 C (the negative sign indicates the charge is negative)

B = 5.01 x 10^-5 T

We can rearrange the formula to solve for v:

v = F / (qB)

Substituting the given values:

v = (-8.11 x 10^-10 N) / (-0.973 x 10^-6 C * 5.01 x 10^-5 T)

v ≈ 16.6 m/s

Therefore, the velocity of the balloon is approximately 16.6 m/s. Option (d) is the correct answer.

Answer: velocity

Explanation:

Your slope is calculated as \(\frac{y_{2}-y_{1}}{x_{2}-x_{1}} =\frac{displacement}{time}\), which equals velocity.

The hertz (Hz) is the SI frequency unit named after the German physicist Heinrich Hertz; one hertz means that an event occurs once every second.

The frequency of a repeating event is the number of occurrences per unit of time. It is distinct from angular frequency and is sometimes referred to as temporal frequency. The unit of frequency is hertz, which equals one event per second. The number of waves that pass through a fixed point in a given amount of time is described by frequency. So, if a wave takes half a second to pass, the frequency is 2 per second. The frequency is 100 per hour if it takes 1/100 of an hour.

Here,

The hertz (Hz) is the SI unit of frequency, named after the German physicist Heinrich Hertz; one hertz means that an event occurs once every second.

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The heating of air inside the balloon causes the volume to expand (Charles's Law), resulting in a decrease in the pressure compared to the surrounding air (Boyle's Law).

Hot-air balloon flight can be explained by the combined principles of Charles's Law, Archimedes' Principle, and Boyle's Law.

Charles's Law states that the volume of a gas is directly proportional to its temperature, assuming the pressure remains constant. In the case of a hot-air balloon, the air inside the balloon is heated, causing the gas molecules to move faster and increase in temperature. As a result, the volume of the gas expands, leading to an increase in the volume of the balloon.

Archimedes' Principle states that an object immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid displaced by the object. In the context of a hot-air balloon, the heated air inside the balloon is less dense than the surrounding cool air. The buoyant force acting on the balloon is equal to the weight of the air displaced by the balloon. This buoyant force is greater than the weight of the balloon itself and the payload, causing the balloon to rise.

Boyle's Law states that the pressure of a gas is inversely proportional to its volume, assuming the temperature remains constant. When the air inside the balloon is heated, the volume increases. As a result, the pressure inside the balloon decreases relative to the surrounding air pressure. The pressure difference creates a net upward force, contributing to the balloon's ascent.

In summary, the combined effects of Charles's Law, Archimedes' Principle, and Boyle's Law explain hot-air balloon flight. The heating of air inside the balloon causes the volume to expand (Charles's Law), resulting in a decrease in the pressure compared to the surrounding air (Boyle's Law). The buoyant force (Archimedes' Principle) acting on the less dense heated air allows the balloon to rise.

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Answer:

middle

top

bottom

under neith middle

Sure! Here are the steps for calculating the velocity and distance traveled by the car after 50 seconds :

Step 1: Calculate the velocity using the equation:

\(v = u + at\)

where:

- \(v\) is the final velocity

- \(u\) is the initial velocity (0 m/s, as the car starts from rest)

- \(a\) is the acceleration (3 m/s²)

- \(t\) is the time (50 seconds)

Substituting the values into the equation:

\(v = 0 + (3 \, \text{m/s²}) \times (50 \, \text{s})\)

Step 2: Calculate the distance traveled using the equation:

\(s = ut + \frac{1}{2}at^2\)

where:

- \(s\) is the distance traveled

- \(u\) is the initial velocity (0 m/s)

- \(a\) is the acceleration (3 m/s²)

- \(t\) is the time (50 seconds)

Substituting the values into the equation:

\(s = 0 \times (50 \, \text{s}) + \frac{1}{2} \times (3 \, \text{m/s²}) \times (50 \, \text{s})^2\)

Now, let's simplify these equations:

\(v = 3 \times 50\)

\(s = \frac{1}{2} \times 3 \times 50^2\)

Calculating the results:

\(v = 150\) m/s

\(s = 3750\) meters

Therefore, after 50 seconds, the car will have a velocity of 150 m/s and would have traveled a distance of 3750 meters.

The flow speed in the hose v1=  2.81 m/s. The flow speed in the nozzle v2= 63.8 m/s

Using the principle of conservation of mass, the mass flow rate in the hose must be equal to the mass flow rate in the nozzle. Thus, we can write:

ρ1A1v1 = ρ2A2v2

where ρ is the density of water, A is the cross-sectional area of the hose or nozzle, and v is the flow speed. Solving for v1 and v2:

v1 = (ρ2A2/A1) v2

v2 = (A1/A2) v1

We are given the diameter of the hose and nozzle, so we can calculate their respective areas:

A1 = π(0.1/2)^2 = 0.00785 m^2

A2 = π(0.021/2)^2 = 0.000346 m^2

The density of water at room temperature is about 1000 kg/m^3. Substituting these values into the equations above:

v1 = (ρ2A2/A1) v2 = (1000 kg/\(m^3\))(0.000346 \(m^2\)/0.00785 \(m^2\)) v2 = 4.38 v2

v2 = (A1/A2) v1 = (0.00785 \(m^2\)/0.000346 \(m^2\)) v1 = 22.7 v1

Now, using the given mass flow rate of 22 kg/s:

ρ1A1v1 = 22 kg/s

v1 = 22 kg/s / (ρ1A1) = 22 / (1000 kg/\(m^3\))(0.00785 \(m^2\)) = 2.81 m/s

Substituting this value into the equation for v2:

v2 = (A1/A2) v1 = (0.00785 \(m^2\)/0.000346 \(m^2\)) (2.81 m/s) = 63.8 m/s

Therefore, the flow speed in the hose is 2.81 m/s and the flow speed in the nozzle is 63.8 m/s.

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Answer:

Fashion and interior design.

I hope it will help you.

Answer:

I think it is protection

Answer:

I think it might be PROTECTION but i not sure for a fact

Sorry if i get it wrong ;]

Explanation:

Answer:

Yes

Explanation:

Yes because Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.

In this scenario, the work being done by the force of friction can be classified as negative work.

Work is defined as the transfer of energy that occurs when a force is applied to an object and it moves through a displacement. The formula for calculating work is W = F * d * cos(theta), where W represents work, F is the magnitude of the force, d is the displacement, and theta is the angle between the force and the direction of the displacement.

In this case, the force being applied is 45N, and the displacement is 9m. The force of friction acts in the opposite direction to the motion, which means it is opposing the movement of your friend as she is being pushed. Therefore, the angle between the force of friction and the direction of displacement is 180 degrees.

When cos(\(180\) degrees) is evaluated, it results in a value of -1. This negative value indicates that the force of friction is acting opposite to the displacement. As a result, the work done by the force of friction is negative.

Negative work signifies that the force of friction is absorbing energy from the system instead of adding energy to it. In the context of your friend's ice skating, the negative work done by the force of friction represents the dissipation of energy as heat due to the resistance between the ice and the skates. This resistance slows down your friend's motion and makes it more difficult for her to maintain her speed or accelerate.

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So, to observe the red traffic light as yellow, the observer must approach the light with a speed of 0.148 times the speed of light.

When the observer approaches the red traffic light with a speed, the light appears shifted towards the blue end of the spectrum. The apparent frequency and wavelength shift is calculated using the Doppler effect equation.

The Doppler shift is given by the relation f′= f (v+vO)/c

where, f' is the observed frequency, f is the frequency of the wave, v is the speed of the observer, v O is the speed of the source and c is the speed of the wave.

For the red traffic light,

f= c/λ = 4.44 × 10^14 Hzλ

= 675 nm

For the yellow traffic light,

f = c/λ

= 5.22 × 10^14 Hzλ

= 575 nm

As we know that the light appears yellow when the red light shifts 575 nm.

Therefore, the observer should be approaching the light with a speed given by the relation as,

∆f/f = v/c⇒ ∆λ/λ

= v/c⇒ v

= c (∆λ/λ)

= c [(λ_0 - λ)/λ_0 ]

Where,λ is the wavelength of the shifted light (λ = 575 nm),λ0 is the wavelength of the unshifted light (λ0 = 675 nm)

Therefore,

v = c [(675 - 575)/675]⇒ v

= 0.148c

So, the observer must approach the red traffic light at a speed of 0.148 times the speed of light to observe it as yellow.

An observer, when approaching a red traffic light, experiences a shift in the light's wavelength towards the blue end of the spectrum. This apparent frequency and wavelength shift is given by the Doppler effect equation.

The Doppler shift can be expressed using the relation,

f′= f (v+vO)/c

where, f' is the observed frequency, f is the frequency of the wave, v is the speed of the observer,v O is the speed of the source and c is the speed of the wave.

The frequency and wavelength of the red and yellow traffic lights are,

f= c/λ

= 4.44 × 10^14 Hz,

λ = 675 nm and

f = c/λ

= 5.22 × 10^14 Hz,

λ = 575 nm.

Since we know that the light appears yellow when the red light shifts by 575 nm, the observer must be approaching the light with a velocity given by the following relation:

∆f/f = v/c⇒ ∆λ/λ

= v/c⇒ v

= c (∆λ/λ_0 ) where λ_0 is the wavelength of the unshifted light (λ_0 = 675 nm)

Therefore,

v = c [(675 - 575)/675]⇒ v

= 0.148c

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Answer:

2*F

Explanation:

If we put an object of a given size exactly at a distance 2*F from the lens, the virtual image (the image generated by the lens) will be generated at a distance 2*F from the lens and the size will be equal to the size of the real object (but the image will be inverted)

Now let's do the math.

The relation between the distance of the object to the lens O, and the distance between the image and the lens I is:

1/O + 1/I = 1/F

solving for O, we get:

1/O = 1/F - 1/I = (I - F)/(F*I)

O = F*I/(I - F)

Such that the relation between the height of the original object, H and the height of the virtual image H' is:

H/H' =  -I/O

Replacing by O we get:

H/H' = -I/(F*I/(I - F))

If the sizes are equal, then H/H' = - 1  (remember that the image is inverted, thus the sign)

-1 = -I/(F*I/(I - F))

F*I/(I - F) = I

F*I = (I - F)*I

F = (I - F)

F + F = I = 2*F

The distance between the image and the lens is 2*F

O =  F*I/(I - F) = F*2*F/(2*F - F) =  2*F

The object is at a distance 2*F from the lens.

Answer:

a=m/f

a=270/30

a=90

this is the correct answer

(a) When the plane of the loop and the magnetic field vector are parallel, the magnetic flux is 0.020 T * π \(m^2\).

The entire magnetic field that flοws thrοugh a specific area is measured by magnetic flux. It serves as a valuable tοοl fοr describing the effects οf the magnetic fοrce οn οbjects inhabiting a certain space. The area selected will have an impact οn hοw magnetic flux is measured.

In this case, we have a circular lοοp with a radius οf 0.10 m and a unifοrm external magnetic field οf 0.20 T.

(a) When the plane οf the lοοp and the magnetic field vectοr are parallel (θ = 0 degrees), the angle between them is 0 degrees. Therefοre, the cοsine οf 0 degrees is 1, and the magnetic flux is:

Φ = B * A * cοs(0) = B * A

Substituting the given values:

Φ = 0.20 T * π * (0.10 m)² = 0.020 T * π m²

(b) When the plane οf the lοοp and the magnetic field vectοr are perpendicular (θ = 90 degrees), the angle between them is 90 degrees. Therefοre, the cοsine οf 90 degrees is 0, and the magnetic flux is:

Φ = B * A * cοs(90) = 0

In this case, the magnetic flux thrοugh the lοοp due tο the external field is zerο.

(c) When the plane οf the lοοp and the magnetic field vectοr are at an angle οf 30 degrees with each οther (θ = 30 degrees), the cοsine οf 30 degrees is √3/2 (apprοximately 0.866), and the magnetic flux is:

Φ = B * A * cοs(30) = B * A * √3/2

Substituting the given values

Φ = 0.20 T * π * (0.10 m)² * √3/2

In summary:

(a) When the plane οf the lοοp and the magnetic field vectοr are parallel, the magnetic flux is apprοximately 0.0628 T·m².

(b) When the plane οf the lοοp and the magnetic field vectοr are perpendicular, the magnetic flux is zerο.

(c) When the plane οf the lοοp and the magnetic field vectοr are at an angle οf 30 degrees, the magnetic flux is 0.20 T * π * (0.10 m)² * √3/2.

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Answer:

the speed of the waves is 150 cm/s

Explanation:

Given;

frequency of the wave, f = 10 Hz = 10

distance between 4 nodes, L = 15.0 cm

The wavelength (λ) of the wave is calculated as follows;

Node to Node = λ/2

L = 2(Node to Node) = (4 Nodes) = 2 (λ/2) = λ

Thus, λ = L = 15.0 cm

The speed (v) of the wave is calculated as follows;

v = fλ

v =  10 Hz   x  15.0 cm

v = 150 cm/s

Therefore, the speed of the waves is 150 cm/s

so the resulting force of all the 3 forces is 11.7 N.

As shown in the figure below ther is 3 forces \(F_1 ,F_2 ,F_3\) are the forces so that the diagram is along the directions given in the question

so \(F_1\) = 3 j^ ( where j^ is unit vector along y axis)

\(F_2\) = 6 cos 45  i^ + 6 sin 45 j^ ( where i^ is unit vector along x axis)

\(F_3\)  = - 5 sin 30 i^ + 5 cos 30 j^

so the resultant force = \(F_1+ F_2 +F_3\)

=> 3 j^ + 4.24 i^ + 4.24 j^ + 4.33 j^ - 2.5 i^

=> 1.74 i^ + 11.57 j^

so resultant force = \(\sqrt{1.74^2 + 11.57^2}\)

=> \(\sqrt{136.89}\)

=> 11.7 N

so the resulting force of all the 3 forces is 11.7 N

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