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
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 5s. 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 ejects its products of combustion at the speed of relative to the jet plane. What is the speed of the latter with respect to an observer on the ground?
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 \((\mathrm{x-t})\) 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 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 and then falls downwards for a time until it reaches the ground. Then:
1. <
2. =
3. >
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