Question

How much work is done by the boy pulling his sister 30.0 m in a wagon as shown in Figure 7.36? Assume no friction acts on the wagon.

Figure 7.36 The boy does work on the system of the wagon and the child when he pulls them as shown.

Short answer

The work done by the boy pulling her sister is $1299\mathrm{J}$.

Step-by-step solution

Definition of Concept

Work: Work is the product of the component of force in the displacement direction and the magnitude of the displacement.

Calculate the work done

Consider the given information:

By applying a force at an angle from the horizontal a boy pulls her sister to a distance of$30.0\mathrm{m}$

The work done is given as,

$W=Fd\cos \theta$

Here,$F$is the magnitude of the force,$d$is the magnitude of displacement, and$\theta$is the angle between the force vector and the displacement vector.

Putting all known values,

$\begin{array}{rl}W& =\left(50.0\mathrm{N}\right)\times \left(30.0\mathrm{m}\right)\times \cos \left({30}^{\circ }\right)\\ & =1299\mathrm{J}\end{array}$

Therefore, the required work is done by the boy pulling her sister is $1299\mathrm{J}$.