Problem 7-65 Energy cons. with friction - D

A box of apples (mass \(22\; kg\)) slides down a ramp inclined at \(44^\circ\) to the horizontal. The fiction force on the box has a magnitude of \(79\; N\). If the box starts from rest and slides \(2.5\; m\) along the ramp, determine:

(a) the work done by friction
(b) the box's final kinetic energy (using conservation of energy)
(c) the thermal energy produced.

[Ans. (a) \(-2.0\times 10^2 \;J\)   (b) \(1.8\times 10^2\; J\)   (c) \(2.0\times 10^2\; J\) ]

Accumulated Solution

FBD with all angles and forces indicated.


The work done by the friction force is given by:

(A)   \(fd\)

(B)   \(fh\)

(C)   \(mgf\)

(D)   \(mgh\)