Q. No.A ball is thrown vertically downwards with a velocity of \(20\) m/s from the top of a tower. It hits the ground after some time with the velocity of \(80\) m/s . The height of the tower is: (assuming \(g = 10~\text{m/s}^2)\)
1.
\(340\) m
2.
\(320\) m
3.
\(300\) m
4.
\(360\) m
If a particle has negative velocity and negative acceleration, its speed:
| 1. | increases |
| 2. | decreases |
| 3. | remains the same |
| 4. | zero |
A particle starts from rest (with constant acceleration) and acquires velocity \(20\) m/s in \(5\) s. The distance travelled by the particle in the next \(2\) s will be:
| 1. | \(50\) m | 2. | \(48\) m |
| 3. | \(100\) m | 4. | \(150\) m |
A drunkard walking in a narrow lane takes \(5\) steps forward and \(3\) steps backward, followed again by \(5\) steps forward and \(3\) steps backward, and so on. Each step is \(1\) m long and requires \(1\) s. There is a pit on the road \(13\) m away from the starting point. The drunkard will fall into the pit after:
1. \(37\) s
2. \(31\) s
3. \(29\) s
4. \(33\) s
The position-time \((x\text-t)\) graphs for two children \(A\) and \(B\) returning from their school \(O\) to their homes \(P\) and \(Q\) respectively are shown in the graph. Choose the incorrect statement.
| 1. | \(B\) reaches home faster than \(A.\) |
| 2. | \(B\) overtakes \(A\) on the road twice. |
| 3. | \(B\) walks faster than \(A.\) |
| 4. | \(A\) lives closer to the school than \(B.\) |
A jet airplane travelling at the speed of \(500~\text{km/h}\) ejects its products of combustion at the speed of \(1500~\text{km/h}\) relative to the jet plane. What is the speed of the latter with respect to an observer on the ground?
1. \(1000~\text{km/h}\)
2. \(500~\text{km/h}\)
3. \(1500~\text{km/h}\)
4. \(2000~\text{km/h}\)
A car moving along a straight highway with a speed of \(126\) km/h is brought to a stop within a distance of \(200\) m. How long does it take for the car to stop?
| 1. | \(10.2\) s | 2. | \(9.6\) s |
| 3. | \(11.4\) s | 4. | \(6.7\) s |
The figure gives the \((x\text-t)\) plot of a particle in a one-dimensional motion. Three different equal intervals of time are shown. The signs of average velocity for each of the intervals \(1,\) \(2\) & \(3,\) respectively are:
| 1. | \(-,-,+\) |
| 2. | \(+,-,+\) |
| 3. | \(-,+,+\) |
| 4. | \(+,+,-\) |
The figure gives a speed-time graph of a particle in motion along the same direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude?
1. Interval 2
2. Interval 1
3. Interval 3
4. Equal in all intervals
A boy standing on a stationary lift (open from above) throws a ball upwards with the maximum initial speed he can, equal to \(49~\text{ms}^{-1}.\) How much time does the ball take to return to his hands?
1. \(5\) s
2. \(10\) s
3. \(15\) s
4. \(7\) s
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