A ball is dropped on the floor from a height of 10 m. It rebounds to a height of 2.5 m. If the ball is in contact with the floor for 0.01 sec, the average acceleration during contact is 

(1) 2100 m/sec² downwards

(2) 2100 m/sec² upwards

(3) 1400 m/sec²

(4) 700 m/sec²

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. $t_1=\frac{t_2}{2}$

2. $t_1=t_2$

3. $t_1=4t_2$

4. $t_1=\frac{t_2}{4}$ 

Velocity of a body on reaching the point from which it was projected upwards, is 

1. $v=0$

2. $v=2u$

3. $v=0.5u$

4. $v=-u$

From the top of a tower, a particle is thrown vertically downwards with a velocity of 10 m/s. The ratio of the distances, covered by it in the 3^rd and 2^nd seconds of the motion is (Take $g=10m/s^2$) 

1. 5 : 7  

2. 7 : 5

3. 3 : 6

4. 6 : 3

When a ball is thrown up vertically with velocity V₀, it reaches a maximum height of 'h'. If one wishes to triple the maximum height then the ball should be thrown with velocity

1. $\sqrt{3}{V}_o$

2. 3 V₀

3. 9 V₀

4. 3/2 V₀

A particle starts from rest. Its acceleration (a) versus time (t) graph is as shown in the figure. The maximum speed of the particle will be:

1. 110 m/s

2. 55 m/s

3. 550 m/s

4. 660 m/s 

A man throws balls with the same speed vertically upwards one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the sky at any time (Given $g=9.8m/s^2)$

(1) At least 0.8 m/s

(2) Any speed less than 19.6 m/s

(3) Only with speed 19.6 m/s

(4) More than 19.6 m/s

The variation of velocity of a particle with time moving along a straight line is illustrated in the following figure. The distance travelled by the particle in four seconds is 

1. 60 m

2. 55 m

3. 25 m

4. 30 m

The displacement of a particle as a function of time is shown in the figure. The figure shows that:

1. The particle starts with a certain velocity but the motion is retarded and finally, the particle stops.

2. The velocity of the particle is constant throughout.

3. The acceleration of the particle is constant throughout.

4. The particle starts with constant velocity, then motion is accelerated and finally the particle moves with another constant velocity.

A ball is thrown vertically upwards. Which of the following graph/graphs represent velocity-time graph of the ball during its flight (air resistance is neglected) 

1. a

2. b

3. c

4. d