A student pulls a laboratory cart along a straight, horizontal track by applying a constant force of magnitude 18N at an angle of 65∘ above the horizontal. The cart moves 0.80m horizontally during the pull.
Assume friction is negligible.
(a) Without performing a numerical calculation, state whether the work done on the cart by the student’s pull is positive, negative, or zero. Explain your reasoning qualitatively in terms of the direction of the force relative to the cart’s displacement.
(b) Describe which component of the applied force is responsible for transferring energy to the cart and explain how the remaining component affects (or does not affect) the cart’s kinetic energy.
(c) Suppose instead the student had pulled with the same force magnitude at 95∘ above the horizontal (slightly backward and upward). Without calculating a value, describe whether the work done in this new situation would be greater than, less than, or equal to the work described in part (a). Justify your answer.