A constant retarding force of 80 N is applied to a body of mass 50 kg which is moving initially with a speed of 20 m/s. What would be the time required by the body to come to rest ?

Options

A. 15 s
B. 14 s
C. 12.5 s
D. 18 s

Answer

C

Explanation

`a=(F)/(m)=(80)/(50)=1.6m//s^(2)` ltbr. `u=20m//s and v=0`
From equation of motion `v=u+at`
`0=20-1.6xxt`
`t=(20)/(1.6)`
`=12.5s`