Question

A stuntman jumps from height of 4.9 m with initial horizontal velocity of 4.5 m/s and lands on ground. How much time stuntman takes to reach ground? (g = 9.8 m/s²)
2s
4.5 s
1 s
1.2 s​

Answer 1

Answer:

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Answer 2

Given :

Height (H) = 4.9 m

Initial horizontal velocity (u) = 4.5 m/sec

To Find :

Time taken by the stuntman to reach the ground.

Solution :

Velocity of the stuntman in y-axis = ucos∅

                                                        = 4.5×cos90

                                                        = 0

Therefore, applying the Kinematic equation for uniformly accelerated body,

s = ut + $\frac{1}{2}$gt²

Where, s = distance covered; u = initial velocity; g = acceleration due to gravity; t = time taken

∴    H   = (0)t + $\frac{1}{2}$gt²

⇒  4.9 =  0  +  $\frac{1}{2}$×9.8×(t)²

⇒   t²  =  1

⇒   t    = √1

∴    t    = 1 s

The time taken by the stuntman to reach the ground  is 1 sec.

Therefore, option (c) is correct