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
\(32ms^{-1} \)
\(50ms^{-1} \)
\(64ms^{-1} \)
\(100ms^{-1} \)
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
\( t = 0.8s \\
\implies 100 = \frac{0.8V - 0.8 \times 0}{0.8} \\
\text{Therefore } V = \frac{100 \times 0.8}{0.8} = 100ms^{-1} \)