I encountered this problem while studying for an exam later this month.

I've drawn the force diagram:

enter image description here

The coefficient of the rolling resistance is given as 0.50.

I know the forces acting upon the sand can be described as:

$F_g=m\cdot g$

$F_1=F_g\cdot \sin (20)$

$F_2=F_g\cdot \cos(20)$


$F_{\mu}=F_n \cdot 0.50$

How do I how do I move on from here?

Any suggestions as to what methods could be used would be very much appreciated.

  • $\begingroup$ The sand slides when the force the conveyor belt applies to it exceeds the static friction which stops it from sliding. No different than a "how hard do you push a block before it slides?" Don't be fooled. $\endgroup$ – DKNguyen May 14 at 2:02
  • $\begingroup$ Thanks for the answer. So if I understand correctly, the maximum acceleration would be the acceleration for which the force is equal to the friction? $\endgroup$ – BatS00p May 14 at 15:24