Two springs of spring constants k and 3k are stretched separately by the same force. The ratio of potential energy stored in them respectively, will be:
1. | 3: 1 | 2. | 9: 1 |
3. | 1: 3 | 4. | 1: 9 |
Mark the correct statement(s):
1. Internal forces cannot increase the kinetic energy of a system.
2. Internal forces may increase the kinetic energy of a system.
3. Work done by kinetic friction is always negative.
4. Both (2) & (3)
A bullet fired towards a wall reduces its kinetic energy by half after the penetration of 6 cm. The further penetration of the bullet into the wall is:
1. 2 cm
2. 1 cm
3. 6 cm
4. 3 cm
A body having an initial kinetic energy 2 J collides with an identical body at rest. The maximum loss of kinetic energy in the collision will be:
1. | 2 J | 2. | Zero |
3. | 1 J | 4. | 1.5 J |
What is the work done by gravity on block A in 2 seconds after the blocks are released? (Pulley is light)
1. 240 J
2. 200 J
3. 120 J
4. 24 J
A weight 'mg' is suspended from a spring. The energy stored in the spring is U. The elongation in the spring is:
1.
2.
3.
4.
The energy required to accelerate a car from rest to 30 m/s is E. The energy required to accelerate the car from 30 m/s to 60 m/s will be:
1. | E | 2. | 2E |
3. | 3E | 4. | 4E |
The speed of a particle moving in a circular path decreases with time. The instantaneous power due to the force acting on it will be:
1. Positive
2. Negative
3. Zero
4. Maybe positive or negative
1. | \(0\%\) | 2. | \(25\%\) |
3. | \(50\%\) | 4. | \(100\%\) |
A body is obliquely projected from the horizontal ground. The magnitude of gravity's power delivered during its motion from the ground to the topmost point is:
1. | Constant
|
2. | Increases continuously
|
3. | Decreases continuously
|
4. | May increase or decrease depending on the angle of projection |