Question

22. An experiment is set-up as shown in the following figure. The upper surface where the spring is located and the slope are frictionless: however, the lower horizontal surface is rough. The height (h) of the upper surface is 0.75 m. A 1.2 kg box is held at rest against a 750 N/m spring such as to compress the spring 0.15 m. The box is released such that it slides along the upper surface and then down the slope. The coefficient of kinetic friction between the box and the lower horizontal surface is 0.295. For full credit, use energy concepts in both parts. (However, this doesn't mean that you won't need some other concepts as well.) (a) What is the speed of the box when it arrives at the bottom of the slope (and before moving on the rough surface)? (b) What distance does the box slide before coming to rest on the rough surface? Upper Surface and Slope are Frictionless Rough Surface Work problems on separate pages.

Please draw the diagrams and write the names of the equations used. Thank you so much.

Answer 1

(A)

$\frac{kx^{2}}{2}+mgh=\frac{mu^{2}}{2}$

$\frac{750*0.15^{2}}{2}+1.2*9.8*0.75=\frac{1.2u^{2}}{2}$

(B)

$2as=v^{2}-u^{2}$

$a=-\mu g$

$-2*0.295*9.8*s=-5.363^{2}$