A body is moving unidirectionally under the influence of a source of constant power supplying energy. Which of the diagrams shown in the figure correctly shown the displacement-time curve for its motion?
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Which of the diagrams shown in the figure most closely shows the variation in kinetic energy of the earth as it moves once around the sun in its elliptical orbit?
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3. | 4. |
Which of the diagrams shown in the figure represents the variation of to mechanical energy of a pendulum oscillating in the air as a function of time.
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3. | 4. |
A mass of \(5~\text {kg}\) is moving along a circular path of radius \(1~\text {m}\). If the mas moves with \(300~\text {rev/min}\), its kinetic energy would be
1. \(250 \pi^2~\text{J}\)
2. \(100 \pi^2~\text{J}\)
3. \(5 \pi^2~\text{J}\)
4. \(0\)
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A cricket ball of mass \(150~\text{g}\) moving with a speed of \(126~\text{km/h}\) hits at the middle of the bat, held firmly at its position by the batsman. The ball moves straight back to the bowler after hitting the bat. Assuming that collision between ball and bat is completely elastic and the two remains in contact for \(0.001~\text{s}\), the force that the batsman had to apply to hold the bat firmly at its place would be:
1. \(10.5~\text{N}\)
2. \(21~\text{N}\)
3. \(1.05\times10^{4}~\text{N}\)
4. \(2.1\times 10^{4}~\text{N}\)
A man of mass \(m,\) standing at the bottom of the staircase, of height \(L,\) climbs it and stands at its top.
(a) | work done by all forces on man is equal to the rise in potential energy \(mgL.\) |
(b) | work done by all forces on man is zero. |
(c) | work done by the gravitational force on man is \(mgL.\) |
(d) | the reaction force from a step does no work because the point of the application of the force does not move while the force exists. |
Choose the correct option:
1. (a), (d)
2. (a), (c)
3. (b), (d)
4. (a), (b), (c)
A bullet of mass \(m\) fired at \(30^\circ\) to the horizontal leaves the barrel of the gun with a velocity \(v.\) The bullet hits a soft target at a height \(h\) above the ground while it is moving downward and emerge out with half the kinetic energy it had before hitting the target. Consider the following statements.
(a) | the velocity of the bullet will be reduced to half its initial value. |
(b) | the velocity of the bullet will be more than half of its earlier velocity. |
(c) | the bullet will continue to move along the same parabolic path. |
(d) | the bullet will move in a different parabolic path. |
(e) | the bullet will fall vertically downward after hitting the target. |
(f) | the internal energy of the particles of the target will increase. |
Which of the above-given statement(s) is/are correct in respect of the bullet after it emerges out of the target?
1. (a), (c), (f)
2. (a), (d), (f)
3. (b), (d, (f)
4. (a), (b), (c)