Question

A constant retarding force of 50n applied to a body of mass 30kg, moving initially with a speed of 18 m/s .How long does it take to come to rest?

Answer 1

Answer:

10.8s

Explanation:

According to Newton's Second Law of Motion:

F=p2-p1/t - (i) (Rate of change of momentum is defined as Force)

Given,

m=30kg, v1=18m/s, v2=0(since coming to rest), F= -50N(Retarding force)

We know: p=mv. Therefore p1=m*v1=30*18=540kgm/s. p2=m*v2=30*0=0kgm/s

Putting the values in the formula (i):

- 50 = (0 - 540)/t

t = 540/50 = 10.8s