A coin is dropped in a lift. It takes time t₁ to reach the floor when lift is stationary. It takes time t₂ when the lift is moving up with constant acceleration. Then:

1. t₁ > t₂

2. t₂ > t₁

3. t₁ = t₂

4. t₁ >> t₂

If the tension in the cable of \(1000~\text{kg}\) elevator is \(1000~\text{kg}\) weight, the elevator:

1. is accelerating upwards.

2. is accelerating downwards.

3. may be at rest or accelerating.

4. may be at rest or in uniform motion.

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 

1. 3 m/sec²

2. –3 m/sec²

3. 0.3 m/sec²

4. –0.3 m/sec²

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 

1. 550 N

2. 50 N

3. 250 N

4. 250 dyne

In the given diagram, the acceleration of the car will be:

1. \(0.25\ \text{m/s}^2\)
2. \(2.5\ \text{m/s}^2\)
3. \(5.0\ \text{m/s}^2\)
4. \(0.025\ \text{m/s}^2\)

A particle of mass \(0.3\ \text{kg}\) is subjected to a force \(F = –kx\) with \(k = 15\ \text{N/m}\). What will be its initial acceleration if it is released from a point \(20\ \text{cm}\) away from the origin:
1. \(5\ \text{m/s}^2\)
2. \(10\ \text{m/s}^2\)
3. \(3\ \text{m/s}^2\)
4. \(15\ \text{m/s}^2\)

An elevator weighing \(6000\ \text{kg}\) is pulled upward by a cable with an acceleration of \(5\ \text{ms}^{–2}\). Taking \(g\) to be \(10\ \text{ms}^{–2}\), the tension in the cable is:
1. \(6000\ \text{N}\)
2. \(9000\ \text{N}\)
3. \(60000\ \text{N}\)
4. \(90000\ \text{N}\)

The ratio of the weight of a man in a stationary lift to that when it is moving downward with uniform acceleration \(a\) is \(3 : 2\). The value of \(a\) is:

1. \(\dfrac 32 g\)

2. \(\dfrac g3\)$\frac{}{}$

3. \(\dfrac 23 g\)

4. \(g\)

If the force on a rocket having an exhaust velocity of \(300\ \text{m/s}\) is \(210\ \text{N}\), then the rate of combustion of the fuel is:

1. \(0.7\ \text{kg/s}\)
2. \(1.4\ \text{kg/s}\)
3. \(0.07\ \text{kg/s}\)
4. \(10.7\ \text{kg/s}\)

In an elevator moving vertically upward with an acceleration \(g\), the force exerted on the floor by a passenger of mass \(M\) is:

1. \(Mg\)

2. \(\dfrac 12 Mg\)

3. Zero

4. \(2 Mg\)