A free 238U nucleus kept in a train emits an alpha particle. When the train is stationary, a nucleus decays and a passenger measures that the separation between the alpha particle and the recoiling nucleus becomes x at time t after the decay. If the decay takes place while the train is moving at a uniform velocity v, the distance between the alpha particle and the recoiling nucleus at a time t after the decay as measured by the passenger is
1. x + v t
2. x – v t
3. x
4. depends on the direction of the train
A reference frame attached to the earth
(a) is an inertial frame by definition
(b) cannot be an inertial frame because the earth is revolving around the sun
(c) is an inertial frame because Newton’s laws are applicable in this frame
(d) cannot be an inertial frame because the earth is rotating about its axis
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (a) and (d)
4. (b) and (d)
A particle stays at rest as seen in a frame. We can conclude that
(a) the frame is inertial
(b) resultant force on the particle is zero
(c) the frame may be inertial but the resultant force on the particle is zero
(d) the frame may be non-inertial but there is a nonzero resultant force
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. All of these
A particle is found to be at rest when seen from a frame S1 and moving with a constant velocity when seen from another frame S2. Mark out the possible options.
(a) Both the frames are inertial
(b) Both the frames are non-inertial
(c) S1 is inertial and S2 is non-inertial
(d) S1 is non-inertial and S2 is inertial
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (a)
4. (a) and (d)
The figures shows the displacement of a particle going along the X-axis as a function of time. The force acting on the particle is zero in the region
(a) AB
(b) BC
(c) CD
(d) DE
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (a) and (c)
4. (c) and (d)
The figure shows a heavy block kept on a frictionless surface and being pulled by two ropes of equal mass m. At t = 0, the force on the left rope is withdrawn but the force on the right end continues to act. Let F1 and F2 be the magnitudes of the forces by the right rope and the left rope on the block respectively.
1. F1 = F2 = F for t < 0
2. F1 = F2 = F + mg for t < 0
3. F1 = F, F2 = F for t > 0
4. F1 < F, F2 = F for t > 0
The force exerted by the floor of an elevator on the foot of a person standing there is more than the weight of the person if the elevator is
(a) going up and slowing down
(b) going up and speeding up
(c) going down and slowing down
(d) going down and speeding up
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. All of these
If the tension in the cable supporting an elevator is equal to the weight of the elevator, the elevator may be:
(a) | going up with increasing speed |
(b) | going down with increasing speed |
(c) | going up with uniform speed |
(d) | going down with uniform speed |
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. all of the above
A particle is observed from two frames \(S_1\) and \(S_2.\) The frame \(S_2\) moves with respect to \(S_1\) with an acceleration \(a.\) Let \(F_1\) and \(F_2\) be the pseudo forces on the particle when seen from \(S_1\) and \(S_2\) respectively. Which of the following are not possible?
1. \(F_1=0,~F_2\neq0\)
2. \(F_1\neq0,~F_2=0\)
3. \(F_1\neq0,~F_2\neq0\)
4. \(F_1=0,~F_2=0\)
A person says that he measured the acceleration of a particle to be nonzero while no force was acting on the particle.
1. | he is a liar |
2. | his clock might have run slow |
3. | his meter scale might have been longer than the standard |
4. | he might have used a non-inertial frame |