A man pushes a wall and fails to displace it. He does:
1. Negative work
2. Positive but not maximum work
3. No work at all
4. Maximum work

The minimum 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° with the horizontal is (given: sin15°=0.2588):
1. 4.36 kJ
2. 5.17 kJ
3. 8.91 kJ
4. 9.82 kJ

A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m. It slides down a smooth surface to the ground, then climbs up another hill of height 30 m and finally slides down to a horizontal base at a height of 20 m above the ground. The velocity attained by the ball is: 

1. 10 m/s

2. $10\sqrt{30}$ m/s

3. 40 m/s

4. 20 m/s

A quarter horse-power motor runs at a speed of 600 r.p.m. Assuming 40% efficiency, the work done by the motor in one rotation will be: 

1. 7.46 J

2. 7400 J

3. 7.46 ergs

4. 74.6 J

Two equal masses, m₁ and m₂ , moving in the same straight line at velocities +3 m/s and –5 m/s respectively, collide elastically. Their velocities after the collision will be:

1. +4 m/s for both

2. –3 m/s and +5 m/s

3. –4 m/s and +4 m/s

4. –5 m/s and +3 m/s

A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on the table is:

1. MgL

2. MgL/3

3. MgL/9

4. MgL/18

A particle of mass 'm' is moving in a horizontal circle of radius 'r' under a centripetal force equal to –K/r², where K is a constant. The total energy of the particle will be:

1. $\frac{K}{2r}$

2. $-\frac{K}{2r}$

3. $-\frac{K}{r}$

4. $\frac{K}{r}$

A force $\mathit{F}=-k(y\mathit{i}+x\mathit{j})$ (where k is a positive constant) acts on a particle moving in the xy-plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a, 0) and then parallel to the y-axis to the point (a, a). The total work done by the force on the particle is:

1. $-\mathrm{2k}{a}^2$

2. $\mathrm{2k}{a}^2$

3. $-k{a}^2$

4. \(ka^2\)

A lorry and a car moving with the same K.E. are brought to rest by applying the same retarding force, then:

1. Lorry will come to rest in a shorter distance

2. Car will come to rest in a shorter distance

3. Both will come to rest in a same distance

4. None of the above

The relationship between force and position is shown in the given figure (in a one-dimensional case). The work done by the force in displacing a body from x = 1 cm to x = 5 cm is:

1. 20 ergs

2. 60 ergs

3. 70 ergs

4. 700 ergs