Chapter 10, Problem 51A

To determine

Amount of work done on the crate.

Answer to Problem 51A

Amount of work done on the crate is $517.5\text{J}$ .

Explanation of Solution

Given:

Angle of inclination, $\theta ={30}^o$

Height, $h=1.15\text{m}$

Applied force, $F=225\text{N}$

Coefficient of friction, $\mu \text{= 0}\text{.28}$

Force exerted is parallel to ramp.

Formula Used:

Work done is given by

  $W=Fs\cos \varphi$    …..     (1)

Calculation:

  

Length of ramp is,

  $\begin{array}{l}s=\frac{1.15}{\sin {30}^o}\\ =2.3\text{m}\end{array}$

Since, force exerted is parallel to ramp. So, there will be zero angle between the force and the displacement.

i.e. $\varphi =0^o$

So. Using (1)

  $\begin{array}{l}W=Fs\cos \varphi \\ =225\times 2.3\times \cos 0^o\\ =517.5\text{J}\end{array}$

Since, work done by person is asked so friction is not considered.