Question

An object of mass M starts from rest at the bottom of a fixed incline of height H. A person decides to push the object up the incline in one of two ways with an applied force shown in the diagram. In each of the trials, the object reaches the top of the incline with speed V. How would the work done by the person on the block compare for the two trials? Assume the same constant non-zero coefficient of kinetic friction between the incline and the object for both trials.
A. More work would be done in trial 1
B. More work would be done in trial 2
C. It is impossible to determine for which trial there would be more work done without knowing the value of the speed V.
D. It is impossible to determine for which trial there would be more work done without knowing the value of the coefficient of kinetic friction.

Answer 1

Correct Answer - A
Using work energy theorem, we get `sumW_(1)=sumW_(2)`
`[W_(g)+W_("friction")]_(1)=[W_(g)+W_("friction")]_(2)`
Since `|f_(1)|gt|f_(2)|implies[W_(ext)]_(1)gt[W_(ext)]_(2)`