A mass of \(1\ \text{kg}\) is suspended by a string \(A\). Another string \(C\) is connected to its lower end as shown in the given figure. If a sudden jerk is given to \(C\), then:

1. The portion \(AB\) of the string will break
2. The portion \(BC\) of the string will break
3. None of the strings will break
4. The mass will start rotating

Subtopic:  Application of Laws |
 60%
Level 2: 60%+
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In the given figure, a mass \(m\) is suspended by string \(A\). Another string \(C\) is connected to its lower end. If the string \(C\) is stretched slowly, then:

                                       

1. The portion \(AB\) of the string will break
2. The portion \(BC\) of the string will break
3. None of the strings will break
4. None of the above

Subtopic:  Application of Laws |
 65%
Level 2: 60%+
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Newton's second law gives the measure of:

1. Acceleration
2. Force
3. Momentum
4. Angular momentum

Subtopic:  Newton's Laws |
 56%
Level 3: 35%-60%
PMT - 1982
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A coin is dropped in a lift. It takes time \(t_1\) to reach the floor when the lift is stationary. It takes time \(t_2\) when the lift is moving up with constant acceleration. Then:
1. \(t_1 > t_2\)
2. \(t_1 < t_2\)
3. \(t_1 = t_2\)
4. \(t_1 >> t_2\)

Subtopic:  Application of Laws |
 65%
Level 2: 60%+
Hints

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.

Subtopic:  Newton's Laws |
 75%
Level 2: 60%+
Hints

An object with a mass \(10\ \text{kg}\) moves at a constant velocity of \(10\ \text{m/s}\). A constant force then acts for \(4\) seconds on the object and gives it a speed of \(2\ \text{m/s}\) in the opposite direction. The acceleration produced in it is:
1. \(3\ \text{m/s}^2\)
2. \(-3\ \text{m/s}^2\)
3. \(0.3\ \text{m/s}^2\)
4. \(-0.3\ \text{m/s}^2\)

Subtopic:  Newton's Laws |
 75%
Level 2: 60%+
PMT - 1971
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A machine gun is mounted on a \(2000\ \text{kg}\) car on a horizontal frictionless surface. At some instant, the gun fires bullets of mass \(10\ \text{g}\) with a velocity of \(500\ \text{m/s}\) with respect to the car. The number of bullets fired per second is ten. The average thrust on the system is:

1. \(550\ \text{N}\)
2. \(50\ \text{N}\)
3. \(250\ \text{N}\)
4. \(250\ \text{dyn}\)

Subtopic:  Newton's Laws |
 72%
Level 2: 60%+
PMT - 1971
Hints

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. \(0.025\ \text{m/s}^2\)

Subtopic:  Application of Laws |
 83%
Level 1: 80%+
PMT - 1971
Hints

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. \(15\ \text{m/s}^2\)

Subtopic:  Spring Force |
 87%
Level 1: 80%+
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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. \(90000\ \text{N}\)

Subtopic:  Application of Laws |
 85%
Level 1: 80%+
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