Question

The momentum of a body of mass 0.5 kg dropped from a certain height (h), when reaches the ground is 10 N s. The value h is _____m. (take $g=10m{s}^{-2}$)

• A. 20
• B. 40
• C. 10
• D. 80

Answer 1

The correct option is A 20

Let the velocity of the body on reaching the ground be 'v'
Momentum of the body on reaching the ground ,
P$=mv=10Ns$
$v=20m/s$
Using equation of motion
$v^2=u^2+2gh$ (u is 0)
$400=2gh$
$h=20m$