Question

A boy is pulling his sister in a wagon. He exerts a force of F = 57 N at an angle of 30°.How much work does the boy do pulling his sister, in joules, if he pulls her 31 m?

Answer 1

Given:

The boy pulls his sister by the force

`F=57\text{ N}`

The force is at an angle of

`\theta=30\degree`

The displacement is,

`d=31\text{ m}`

To find:

The work by the boy

Step-by-step explanation:

The component of the force along the displacement is,

`\begin{gathered} Fcos\theta=57* cos30\degree \\ =49.4\text{ N} \end{gathered}`

The work done by the boy in pulling his sister is,

`\begin{gathered} W=Fcos\theta* d \\ =49.4*31 \\ =1531.4\text{ J} \end{gathered}`

Hence, the work is 1531.4 J.