Question

A force of 40 N acting on a body for 5 seconds displaces the body by 100 m along a straight line. If the body starts from rest, calculate the mass of the body. If the force ceases to act at the end of 5 seconds, calculate the distance travelled by the body in the next 5 seconds.​

Answer 1

Let mass be 'm'

$F=ma\\a=F/m\\a=40/m\\s=ut+\frac{at^2}{2}\\100=0(5)+\frac{40}{m}*\frac{5^2}{2}\\100=\frac{40}{m}*\frac{25}{2}\\\\100=\frac{500}{m}\\\\m=5kg$