Question

a body of mass 5 kg initially at rest is subjected to a force of 20 Newton what is the kinetic energy acquired by the body at the end of 10 seconds

Answer 1

Hi friend,

Force = mass × acceleration

A= F/m

a= 4 m/s ².

We know that,

K.e = 1/2 mv²

To find v:-

V= u+at

V= 0+40
V= 40 m/s.

K.E = 1/2 ×5×40×40

K.E =4000 J.

Hope this helped you a little!!!

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Answer 2

F=M×a
$20 = 5a \\ a = 4m {sec}^{ - 2}$
$acceleration \: is \: constant \: so \: use \: equation \: of \: motion \\ \\ \: v = u + at \\ u = 0 \: t = 10 \: a = 4 \\ so \\ v = 40$
Now kinetic energy at the end of 10 sec.

$= \frac{1}{2} m {v}^{2} \\ = \frac{1}{2} 5 \times {40}^{2} \\ = 4000 joules$
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