Processing math: 66%
Home / Aptitude Tests / Physics / A force of 100N was ...

A force of 100N was used to kick a football of mass 0.8kg...

A force of 100N was used to kick a football of mass 0.8kg. Find the velocity with which the ball moves if it takes 0.8s to be kicked

A.

32ms1

B.

50ms1

C.

64ms1

D.

100ms1

Correct answer is D

From Newton's second law:

F = \frac{mV - mµ}{t}

Let the final velocity = V; and since the football is initially at rest, its initial vel µ = 0, M = 0.8kg

t = 0.8s \\ \implies 100 = \frac{0.8V - 0.8 \times 0}{0.8} \\ \text{Therefore } V = \frac{100 \times 0.8}{0.8} = 100ms^{-1}