1. A body of mass 40 gm is moving with a constant velocity of 2 cm/sec on a horizontal frictionless table. The force on the table is

a) 39200 dyne

b) 160 dyne

c) 80 dyne

d) Zero dyne

Explanation: Force on the table = mg = 40 * 980 = 39200 dyne

2. When 1 N force acts on 1 kg body that is able to move freely, the body receives

a) A speed of 1 m/sec

b) An acceleration of \[1 m\diagup sec^{2}\]

c) An acceleration of \[980 cm\diagup sec^{2}\]

d) An acceleration of \[1 cm\diagup sec^{2}\]

Explanation:

3. An object with a mass 10 kg moves at a constant velocity of 10 m/sec. A constant force then acts for 4 second on the object and gives it a speed of 2 m/sec in opposite direction. The acceleration
produced in it, is

a) 3 \[m\diagup sec^{2}\]

b) -3 \[m\diagup sec^{2}\]

c) 0.3 \[m\diagup sec^{2}\]

d) -0.3 \[m\diagup sec^{2}\]

Explanation:

4. In the above question, the force acting on the object

a) 30 N

b) – 30 N

c) 3 N

d) – 3 N

Explanation: F = ma = 10 * (−3) = −30 N

5. In the above question, the impulse acting on the object is

a) 120 Newton \[\times\] sec

b) -120 Newton \[\times\] sec

c) 30 Newton \[\times\] sec

d) -30 Newton \[\times\] sec

Explanation: Impulse = Force * Time = −30 * 4 = −120 N-s

6. A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant the gun fires bullets of mass 10 gm with a velocity of 500 m/sec with respect to the car. The number of bullets fired per second is ten. The average
thrust on the system is

a) 550 N

b) 50 N

c) 250 N

d) 250 dyne

Explanation:

7. In the above question, the acceleration of the car will be

a) 0.25 \[m\diagup sec^{2}\]

b) 25 \[m\diagup sec^{2}\]

c) 5.0 \[m\diagup sec^{2}\]

d) 0.025 \[m\diagup sec^{2}\]

Explanation:

8. A particle of mass 0.3 kg is subjected to a force \[k=-kx\] with \[k=15N\diagup m\] . What will be its initial acceleration if it is released from a point 20 cm
away from the origin

a) 5 \[m\diagup sec^{2}\]

b) 10 \[m \diagup sec^{2}\]

c) 3 \[m\diagup sec^{2}\]

d) 15 \[m\diagup sec^{2}\]

Explanation:

9. A block of metal weighing 2 kg is resting on a frictionless plane. It is struck by a jet releasing water at a rate of 1 kg/sec and at a speed of 5
m/sec. The initial acceleration of the block will be

a) \[2.5m\diagup sec^{2}\]

b) \[5.0m\diagup sec^{2}\]

c) \[10m\diagup sec^{2}\]

d) None of the above

Explanation:

10. Gravels are dropped on a conveyor belt at the rate of 0.5 kg/sec. The extra force required in newtons to keep the belt moving at 2 m/sec is

a) 1

b) 2

c) 4

d) 0.5

Explanation: