Work Energy Theorem Application

Q. A mass m slides down a plane inclined at an angle $\alpha$ to the horizontal. The height of the inclined plane is h and the coefficient of friction over both surface is $\mu$. Then the distance that it will move on the horizontal plane after covering the entire length of the inclined plane.

1. h- h/tanα
2. h/μ - h/tanα
3. h/μ – h
4. h/μ - 1/tanα

Q.

Consider the following two statements

1.Linear momentum of a system of particles is zero

2.Kinetic energy of a system of particles is zero

Then

1. implies 2 and 2 implies 1

2. 1 does not imply 2 and 2 does not imply 1

3. 1 does not imply 2 but 2 implies 1

4. 1 implies 2 but 2 does not imply 1

Q. What is work done in displacing a pendulum with a massless string and a bob of mass 'm' to an angle $\theta$?. Assume that the bob is in equilibrium at every point in the path.

1. mgL(sin$\theta$)
2. mgL(1-cos$\theta$)
3. mgL(1-sin$\theta$)
4. mgL(tan$\theta$)

Q. A rifle bullet loses ${\frac{1}{20}}^{th}$ of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is

1. 5
2. 10
3. 11
4. 20

Q.

The only force acting on a 2.0 kg body as it moves along the x - axis varies as shown in the figure. The velocity of the body at x = 0 is 4.0 $\frac{m}{s}$ What is the maximum K.E attained by the body between x=0 and x=5 m?

1. 18 J

2. 20 J

3. 16 J

4. 12 J

Q.

The work done in pulling up a block of wood weighing 2 kN for a length of 10m on a smooth plane inclined at an angle of ${15}^{\circ }$ with the horizontal is

1. 4.36 kJ

2. 5.17 kJ

3. 8.91 kJ

4. 9.82 kJ

Q.

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

1. Doubled

2. The same

3. Halved

4. Four times

Q.

An open knife edge of mass m is dropped from a height h on a wooden

floor. If the blade penetrates upto the depth d into the wood, the average resistance offered by the wood to the knife edge is

1. 

2. 

3. 

4. 

Q.

A rifle bullet loses $1/{20}^{th}$ of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is

1. 10

2. 5

3. 20

4. 11

Q. A uniform chain of length 2m is kept on a table such that a length of 60cm hangs freely from the edge of the table. The total mass of the chain is 4kg. What is the work done in pulling the entire chain on the table

1. 7.2 J
2. 3.6 J
3. 120 J
4. 1200 J