Given:
The boy pulls his sister by the force
[tex]F=57\text{ N}[/tex]The force is at an angle of
[tex]\theta=30\degree[/tex]The displacement is,
[tex]d=31\text{ m}[/tex]To find:
The work by the boy
Explanation:
The component of the force along the displacement is,
[tex]\begin{gathered} Fcos\theta=57\times cos30\degree \\ =49.4\text{ N} \end{gathered}[/tex]The work done by the boy in pulling his sister is,
[tex]\begin{gathered} W=Fcos\theta\times d \\ =49.4\times31 \\ =1531.4\text{ J} \end{gathered}[/tex]Hence, the work is 1531.4 J.
