# A truck pulls boxes up an incline plane. The truck can exert a maximum force of 4,000 N. If the plane's incline is pi/3  and the coefficient of friction is 4/3 , what is the maximum mass that can be pulled up at one time?

Let the maximum mass that can be pulled at one time be $m$.
Here,$F = m g \sin \left(\frac{\pi}{3}\right) + \mu m g \cos \left(\frac{\pi}{3}\right)$
Putting the values of $F \mathmr{and} \mu$
$4000 = m \left[10 \times \frac{\sqrt{3}}{2} + \frac{4}{3} \times 10 \times \frac{1}{2}\right]$