Potential energy of a body is the energy possessed by the body by virtue of its position. P.E.`=mgh` where the symbols have their usual meaning. Kinetic energy of a body is the energy possessed by the body by virtual of its velocity.
`K.E.=(1)/(2)m upsilon^(2)`
Energy can neither be created nor be destroyed. However energy can be changed from one form to other, such that energy appearing in one form is equal to the energy disappearing in the other form.
With the help of the passage given above, choose the most appropriate alternative for each of the following question `:`
A body of mass `1 kg` is allowed to fall freely under gravity. The momentum of the body 5 second after it starts falling is

Options

A. `100 kg ms^(-1)`
B. `50 kg ms^(-1)`
C. `150 kg ms^(-1)`
D. `200 kg ms^(-1)`

Answer

B

Explanation

Here,` m=1 kg u =0, t = 5 s , p=?`
`upsilon=u+at`
`upsilon=0+10xx5=50m//s`
`p= m upsilon = 1xx50= 50 kg m s ^(-1)`