Question

A body having mass 100 gram is allowed to fall freely under the gravity. Find its kinetic energy after 10 sec.(g = 1000cm / sec^2) ?

Answer 1

As it is falling freely due to gravitational force only,we can apply the equation `v=u+g t` (where, `v` is the velocity acquired after travelling for `t s` with an initial velocity of `u` under accelerartion `g`)

Here, `u=0,t=10,g=1000`

So,`v=1000*10=10^4 (cm)/s`

So,kinetic energy after `10s` will be `1/2 mv^2 = 1/2*100*(10^4)^2=50*10^8 erg` or, `500 J`