Law of conservation of energy

Q.

The mechanical energy in a system remains constant.

1. True

2. False

Q.

An object is dropped from a height $h$, when is its kinetic energy maximum?

Q.

Does the transfer of energy take place when you push a huge rock with all your might and fail to move it?

Q.

A ball rolling on the floor has _______ potential energy.

Q.

What type of energy is possessed by a stone lying on the roof of a house?

Q.

A car is accelerated on a levelled road and attains a velocity $4$ times of its initial velocity. In this process the potential energy of the car

1. does not change

2. becomes twice to that of initial

3. becomes $4$ times that of initial

4. becomes $16$ times that of initial

Q.

Discuss the various forms of mechanical energy.

Q. A body of mass 3 kg is dropped from a height of 1m. The K.E of the body before touching the ground is:

1. 150 J
2. 29.4 N
3. 29.4 J
4. 150 N

Q.

A man eats glucose and then he makes a block move, which then comes to rest after sliding on a rough floor. The correct order of energy changes can be:

1. Chemical - Heat - Kinetic

2. Chemical - Kinetic - Heat

3. Heat - Kinetic - Chemical

4. Kinetic - Chemical- Heat

Q. The P.E.of a body at a certain height is 200J when it is released. The K.E when it just touches the surface is:

1. Equal to P.E
2. Cannot determine
3. Greater than P.E
4. Lesser than P.E

Q. A runner possesses only kinetic energy. What kind of energy is possessed by a bird?

1. Potential energy only
2. Both kinetic and potential energy
3. Kinetic energy
4. Can't say

Q. Work done by an object is independent of the path.

1. True
2. False

Q.

A $4kg$ projectile is launched vertically from a height of $2m$ with an initial speed of $12m{s}^{-1}$. Find its speed (to nearest integer) when it is at a height of $3m$ above the ground.

1. $10m{s}^{-1}$

2. $12m{s}^{-1}$

3. $13m{s}^{-1}$

4. $11m{s}^{-1}$