Kinetic Energy

Q.

Can the kinetic energy of a body be negative?

Q.

A mass of 10 kg is dropped from a height of 50 cm. Find its:
(a) kinetic energy, and (b) velocity
Just as it reaches the ground, does the velocity depend on the mass of the particles? Explain.

Q.

State the energy changes taking place when a car moves up a hilly road.

Q.

What do you mean by energy? Explain different kinds of mechanical energy.

Q.

A rocket is moving up with a velocity v. If the velocity of this rocket is suddenly tripled, what will be the ratio of two kinetic energies?

Q. A bullet of mass $100g$ has attained a velocity of $1080km{h}^{-1}$ towards the target. What would its kinetic energy be at that moment?

1. $4300J$
2. $4750J$
3. $4500J$
4. $4240J$

Q.

A moving bullet possesses

1. kinetic energy

2. mechanical energy

3. chemical energy

4. light energy

Q.

The birds flying high in the sky possess kinetic energy and ________ energy.

Q. Which of the following objects have non-zero kinetic energy?

1. Moving car
2. Flying birds
3. Sitting man
4. Rolling ball

Q. What kind of energy is associated with the motion of an athlete?

1. No energy
2. Electrical energy
3. Nuclear energy
4. Kinetic energy

Q.

An object is falling from a terrace (height 20m). At what point does it have the maximum kinetic energy?

1. 20m height

2. 10m height

3. When object touched the ground floor

4. Just before touching the ground floor

Q.

The point of minimum kinetic energy in case of oscillating pendulum is ____________ position. (extreme or mean).

Q.

An object of mass $\mathrm{m}$ is moving with a constant velocity $v$. How much work should be done on the object in order to bring the object to rest?

Q. Kinetic energy can be increased by increasing the______.

1. Height
2. Volume
3. Pressure
4. Speed

Q. Look at the given diagram. At which point does the ball have minimum kinetic energy?

1. B
2. D
3. C
4. A

Q.

On which of the following factors does the kinetic energy of a body depend?

1. Mass of the body

2. Height of the body above Earth’s surface

3. Speed of the body

4. Shape of the body

Q.

Two formula one cars in a race have the same mass but their kinetic energies are different. The ratio of their kinetic energies is 1:16. What would be the corresponding ratio of their velocities?

1. 4:1

2. 1:4

3. 2:1

4. 1:2

Q. A train moving on the ground has mechanical energy in the form of ___________. (Consider ground to be the reference point).

1. potential energy
2. chemical energy
3. kinetic energy
4. heat energy

Q.

Where is energy stored?

Q.

In which of the following cases will a small wooden box move the furthest?

Case 1: A bowling ball is thrown at the box

Case 2: A tennis ball is thrown at the box

Case 3: A ping-pong ball is thrown at the box

Case 4: A cricket ball is thrown at the box

1. Case 1

2. Case 2

3. Case 4

4. Case 3

Q.

An object is falling from a terrace (height 20 m). At what point does it have maximum kinetic energy?

1. 10m height

2. When object touched the ground floor

3. Just before touching the ground floor

4. 20m height

Q.

A child is moving on a skateboard at the speed of 2 m/s. After a force acts on him, his speed becomes 3 m/s. What is the work done by the external force on the child, given the weight of the child is 20 kg?

1. 20 J
2. 320 J
3. 50 J

4. 100 J

Q. Concept of Kinetic energy

Q. If air resistance is zero, the sum of potential and kinetic energy of a freely falling body will:

1. remain constant
2. zero
3. decrease
4. increase

Q. a person standing on rotating platform has his hands lowered . if he suddenly outstretch his arm then what change is expected in angular momentum and in rotational kinetic energy ?

Q. power = energy/time
= mgh / t
= mv^​2 / 2t
if we cancel t, then we will get 1/2 mv² = mgh . Is this true ?
if its true then potential enrgy will always be equal to kinetic enrgy ?

Q.

What is energy? Explain conservation of energy with an example. [3 MARKS]

Q.

A cylindrical cell is rolling down an inclined plane. Name the energy possessed by the cell as it rolls down.