Question

a force of 10 Newton acts for 20 seconds on a body of mass 2 kg initially at rest calculate the energy required by the body and the work done by the applied force​

Answer 1

Given:

A force of 10 Newton acts for 20 seconds on a body of mass 2 kg initially at rest.

To find:

• Work done by force?

Calculation:

Let's calculate the displacement:

$\sf d = ut + \dfrac{1}{2} a {t}^{2}$

$\sf \implies d = (0)t + \dfrac{1}{2} \times \dfrac{force}{mass} \times {t}^{2}$

$\sf \implies d = \dfrac{1}{2} \times \dfrac{10}{2} \times {(20)}^{2}$

$\sf \implies d = 1000 \: m$

• Work done by a force is calculated as the scalar product between force vector and displacement vector.

• When both the vectors are parallel, we say :

$\sf \: W = F \times d$

$\sf \implies \: W = 10 \times 1000$

$\sf \implies \: W = {10}^{4} \: joule$

So, work done is 10⁴ Joule.