A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of `15m s^-1`. How long does the body take to stop ?

Explanation

Retarding force =50N `rArr` mass = 20kg
`-F= ma a= -(F)/(m)= (50)/(20)= (5)/(2) ms^(-2)`
We know that `v= u + a t, 0= 15 - (5)/(2)t rArr t= (15 xx 2)/(5)= 6` sec