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
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 |
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 |
A helicopter moving vertically upwards releases a packet when it is at a certain height above the ground. The packet initially moves upwards for a time \(t_1\) and then falls downwards for a time \(t_2\) until it reaches the ground. Then:
| 1. | \(t_1<t_2\) | 2. | \(t_1=t_2\) |
| 3. | \(t_1>t_2\) | 4. | Data insufficient |
A car moves with a speed of \(60\) km/h for \(1\) hour in the east direction and with the same speed for \(30\) min in the south direction. The displacement of the car from the initial position is:
| 1. | \(60\) km | 2. | \(30 \sqrt{2}\) km |
| 3. | \(30 \sqrt{5}\) km | 4. | \(60 \sqrt{2}\) km |
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