An iron ball and a wooden ball of the same radius are released from a height ‘h’ in a vacuum. The time taken by both of them to reach the ground is
1. Unequal
2. Exactly equal
3. Roughly equal
4. Zero
Two trains along the same straight rails moving with constant speed 60 km/hr and 30 km/hr respectively towards each other. If at time t = 0, the distance between them is 90 km, the time when they collide is:
1. 1 hr
2. 2 hr
3. 3 hr
4. 4 hr
A particle when thrown moves such that it passes from the same height at 2 sec and 10 sec, the height is:
1. g
2. 2g
3. 5g
4. 10g
Time taken by an object falling from rest to cover the height of h1 and h2 is respectively t1 and t2 . Then the ratio of t1 to t2 is
1. h1 : h2
2.
3. h1 : 2h2
4. 2h1 : h2
Velocity of a body on reaching the point from which it was projected upwards, is
1.
2.
3.
4.
A ball of mass m1 and another ball of mass m2 are dropped from equal height. If time taken by the balls are t1 and t2 respectively, then
1.
2.
3.
4.
1. | It reaches \(\frac{H}{2}\) in \(\frac{T}{2}\) sec |
2. | It acquires velocity \(\frac{u}{2}\) in \(\frac{T}{2}\) |
3. | Its velocity is \(\frac{u}{2}\) at \(\frac{H}{2}\) |
4. | Same velocity at \(2T\) |
A man in a balloon rising vertically with an acceleration of releases a ball 2 sec after the balloon is let go from the ground. The greatest height above the ground reached by the ball is
1. 14.7 m
2. 19.6 m
3. 9.8 m
4. 24.5 m
The distance between two particles is decreasing at the rate of \(6\) m/sec when they are moving in the opposite directions. If these particles travel with the same initial speeds and in the same direction, then the separation increases at the rate of \(4\) m/sec. It can be concluded that particles' speeds could be:
1. \(5\) m/sec, \(1\) m/sec
2. \(4\) m/sec, \(1\) m/sec
3. \(4\) m/sec, \(2\) m/sec
4. \(5\) m/sec, \(2\) m/sec
A 210-meter long train is moving due north at a speed of 25 m/s. A small bird is flying due South a little above the train with a speed of 5m/s. The time taken by the bird to cross the train is
1. 6 s
2. 7 s
3. 9 s
4. 10 s