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3 years ago

A ball is falling after rolling off a tall roof The ball has what type of energy.

Physics

1 answer:

CaHeK987 [17]3 years ago

3 0

Answer:

Linear and rotational Kinetic Energy + Gravitational potential energy

Explanation:

The ball rolls off a tall roof and starts falling.

Let us first consider the potential energy or more specifically gravitational potential energy ( $mgh$ ; $m$ = mass of the ball, $g$ = acceleration due to gravity, $h$ = height of the roof). This energy comes because someone or something had to do work to take the ball to the top of the roof against the force of gravity. The potential energy is naturally maximum at the top and minimum when the ball finally reaches the ground.

Now, the ball starts to roll and falls off the roof. It shall continue rotating because of inertia (Newton's first law). This contributes to the rotational kinetic energy ( $\frac{1}{2}I\omega^2$ ; $I$ =moment of inertia of the ball & $\omega$ = angular velocity).

Finally comes the linear kinetic energy or simply, kinetic energy ( $\frac{1}{2}mv^2$ ) which is caused due to the velocity $v$ of the ball.

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statuscvo [17]

Explanation:

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3 years ago

A 2.64-kg copper part, initially at 400 K, is plunged into a tank containing 4 kg of liquid water, initially at 300 K. The coppe

marin [14]

Answer:

a) $T_f=305.7049\ K$

b) $\Delta S=313.51\ J.K^{-1}$

Explanation:

Given:

mass of copper, $m_c=2.64\ kg$

initial temperature of copper, $T_{ic}=400\ K$

specific heat capacity of copper, $c_c=385\ J.kg^{-1}.K^{-1}$

mass of water, $m_w=4\ kg$

initial temperature of water, $T_{iw}=300\ K$

specific heat capacity of water, $c_w=4200\ J.kg^{-1}.K^{-1}$

<u>∵No heat is lost in the environment and the heat is transferred only between the two bodies:</u>

Heat rejected by the copper = heat absorbed by the water

$2.64\times 385\times (400-T_f)= 4\times 4200\times (T_f-300)$

$T_f=305.7049\ K$

<u>Now the amount of heat transfer:</u>

$Q=m_c.c_c.(T_{ic}-T_{f})$

$Q=2.64\times 385\times (400-305.7049)$

$Q=95841.5841\ J$

∴Entropy change

$\Delta S=\frac{dQ}{T}$

$\Delta S=\frac{95841.5841}{305.7049}$

$\Delta S=313.51\ J.K^{-1}$

5 0

4 years ago

On a cold winters da,y,If you left a drink setting outside,it could freeze.Explain why in a complete sentence

sertanlavr [38]

Hello!

On a cold winters day, if you left a drink setting outside, it could freeze because the heat (related to the kinetic energy) of the atoms in the drink will be transferred to the environment to achieve energy equilibrium.

Heat transfer occurs by various mechanisms, flowing from the hottest body to the coldest, that's why the heat goes from the drink, which has a higher temperature (and kinetic energy) to the environment, which has a lower temperature. This is described by the second law of thermodynamics

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4 years ago

If you apply a net force of 5N on a cart with a mass of 5 kg, show that the acceleration is 1 m/s2.

Svetlanka [38]

Answer: F = 5kg x 1 m/s2 = 5 N

Explanation:

Hi, to answer this question we have to apply the next formula:

Force (F) = mass x acceleration

Replacing with the values given and solving for F (force)

F = 5kg x 1 m/s2 = 5 kgm/s2

Since 1 Newton (N) = 1 kgm/s2

F = 5N

Feel free to ask for more if needed or if you did not understand something.

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4 years ago

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