Question

An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s^-2, then the velocity of object on reaching the ground will be 

विकल्प

•  9.8 m s^-1

• 4.9 m s^-1

• 19.6 m s^-1

• Zero

Answer 1

An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s^-2, then the velocity of object on reaching the ground will be 19.6 m s^-1 

METHOD: Given, u = 0

g = 9.8 m/s²

Time t = 2s

Let 'v' be the velocity of object on reaching the ground.

Using the first equation of motion,

v = u + gt

We get,

v = 0 + (9.8) (2)

Or, v = 19.6 m/s.