A body projected vertically upwards with a velocity u returns to the starting point in 4 seconds. If g = 10m/sec², the value of u is  

1. 5 m/sec

2. 10 m/sec

3. 15 m/sec

4. 20 m/sec

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. $\sqrt{h_1}:\sqrt{h_2}$

3. h₁ : 2h₂

4. 2h₁ : h₂

A body is thrown vertically up from the ground. It reaches a maximum height of \(100\) m in \(5\) s. After what time will it reach the ground from the position of maximum height?

A body thrown vertically upwards with an initial velocity u reaches maximum height in 6 seconds. The ratio of the distances travelled by the body in the first second and the seventh second is 

1. 1 : 1

2. 11 : 1

3. 1 : 2

4. 1 : 11

A particle is thrown vertically upwards. If its velocity at half of the maximum height is 10 m/s, then maximum height attained by it is (Take g = 10 m/s²) 

1. 8 m

2. 10 m

3. 12 m

4. 16 m

A body, thrown upwards with some velocity, reaches the maximum height of 20m. Another body with double the mass thrown up, with double initial velocity will reach a maximum height of 

1. 200 m

2. 16 m

3. 80 m

4. 40 m

A balloon starts rising from the ground with an acceleration of 1.25 m/s² . After 8s, a stone is released from the balloon. The stone will (g = 10 m/s²) 

1. Reach the ground in 4 second

2. Begin to move down after being released

3. Have a displacement of 50 m

4. Cover a distance of 40 m in reaching the ground

A body is thrown vertically upwards with a velocity u. Find the true statement from the following:

1. Both velocity and acceleration are zero at its highest point

2. Velocity is maximum and acceleration is zero at the highest point

3. Velocity is maximum and acceleration is g downwards at its highest point

4. Velocity is zero at the highest point and maximum height reached is $u^2/2g$

A man throws a ball vertically upward and it rises through 20 m and returns to his hands. What was the initial velocity (u) of the ball and for how much time (T) it remained in the air $[g=10m/s^2]$ 

1. u = 10 m/s, T = 2s

2. u = 10 m/s, T = 4s

3. u = 20 m/s, T = 2s

4. u = 20 m/s, T = 4s

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