Question

A stone is thrown vertically upwards with a velocity of 4.9 m/s calculate the time taken to reach the ground

Answer 1

Heya
here the initial velocity = u = 4.9 m/s
as the body is thrown upward
final velocity = v = 0 m/s
and acceleration = a = -9.8 m/s²
time = ?
as the body is thrown upward defying the gravity.

a = ( v - u )/ t
So,
t = ( v - u )/ a
= (0-4.9)/-9.8
= -49/10 × 10/-98
= -49/-98
= 1/2
= 0.5 sec

So it will take 0.5 sec to reach the highest point
Hence it will take 2×0.5= 1sec to reach the ground.


HOPE THIS HELP

Answer 2

If time taken to reach maximum height is t then
v = u + at
0 = u + (-gt)
t = u/g ………(1)

Total Time taken to reach the ground (T) = 2t
T = 2u/g …………[∵ from (1)]
= (2 × 4.9 m/s) / (9.8 m/s²)
= 1 second

∴ Time taken for stone to reach the ground is 1 second