Answer:
3.38 m/s
Explanation:
Mass of child = m₁ = 25
Initial speed of child = u₁ = 5 m/s
Initial speed of cart = u₂ = 0 m/s
Mass of cart = m₂ = 12 kg
Velocity of cart with child on top = v
This is a case of perfectly inelastic collision

Velocity of cart with child on top is 3.38 m/s
A large force is required to accelerate the mass of the bicycle and rider. Once the desired constant velocity is reached, a much smaller force is sufficient to overcome the ever-present frictional forces.
Answer:
A) some of the rocks energy is transformed to thermal energy
Explanation:
If we neglect air resistance during the fall of the rock, than the mechanical energy of the rock (which is sum of its potential energy and its kinetic energy) would be constant during the entire motion, so the total energy of the rock at the top would be the same as the sum of its potential energy and kinetic energy at the bottom.
However, this not occurs, due to the presence of air resistance. In fact, air resistance acts against the fall of the rock, and because of the friction between the molecules of air and the surface of the rock, the rock loses part of its energy. This energy is converted into thermal energy of the molecules of the air.
-- pushing on a brick wall
-- standing on your little brother's back so that he can't get up
-- taking a nap while on the job
-- squeezing anything that doesn't yield to your squeeze, such as a glass bottle or your girl friend
-- watching TV
-- solving math problems in your head
-- making pictures out of clouds in the sky
Answer:

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♨ Question :
- A car starts from rest and is moving at 60.0 m/s after 7.50 s. What is the car's average acceleration ?
♨ 
☄ Given :
- Initial velocity ( u ) = 0
- Final velocity ( v ) = 60.0 m/s
- Time ( t ) = 7.50 s
☄ To find :
✒ We know ,

Substitute the values and solve for a.
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✑ Additional Info :
- When a certain object comes in motion from rest , in the case , initial velocity ( u ) = 0
- When a moving object comes in rest , in the case , final velocity ( v ) = 0
- If the object is moving with uniform velocity , in the case , u = v.
- If any object is thrown vertically upwards in the case , a = -g
- When an object is falling from certain height , in the case , final velocity at maximum height ( v ) = 0.
Hope I helped!
Have a wonderful time ツ
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