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 |
Two trains A and B of length \(400\) m each are moving on two parallel tracks with a uniform speed of \(72\) km/h in the same direction with A ahead of B. The driver of B decides to overtake A and accelerates by \(1\) m/s2. If after \(50\) s, the guard of B just brushes past the driver of A, what was the original distance between them?
1. \(2000\) m
2. \(2250\) m
3. \(1200\) m
4. \(1250\) m
On a two-lane road, car A is travelling at a speed of \(36\) kmh–1. Two cars B and C approach car A in opposite directions with a speed of \(54\) kmh–1 each. At a certain instant, when the distance AB is equal to AC, both being \(1\) km, B decides to overtake A before C does. What minimum acceleration of car B is required to avoid an accident?
1. \(1\) ms–2
2. \(5\) ms–2
3. \(2\) ms–2
4. \(3\) ms–2
A player throws a ball upwards with an initial speed of . What is the direction of acceleration during the upward motion of the ball?
1. | vertically downwards |
2. | vertically upwards |
3. | first upwards then downwards |
4. | none of the above |
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