Question

A body of mass 5kg initially at rest is subjected to force of 20n. What is the kinetic energy acquired by the body at the end of 2s

Answer 1

$f = m \times a$

$20 = 5 \times a$
$a = 20 \div 5 = 4$
$v = u + a \times t$
u=0
because body
initially at rest
$v = a \times t = 4 \times 2 = 8$
$ke = 1 m{v}^{2} \div 2$
$ke = 5 \times 64 \div 2 = 160$