Question

QUESTION 2 (1 ma o n of energy in relation to work S You are given a box on an incline and we asked to push it up 5 m state what angle of force with respect to the box would make the task easiest. (1 mark) Explain why (1 mark) CONFIDENTI

Answer 1

(1) Energy is the capacity to do work

(2)

mg cose mg sine mg cose mg F

Figure shows a box placed on inclined plane and the forces acting on the box

weight mg acting downward is resolved into two component i.e., (1) mgsin$\theta$ parallel to inclined plane and

(2) mgcos$\theta$ perpendicular to inclined plane.

Reaction force by incline plane surface to box also shown as mgcos$\theta$ acting upward at the box

Force component mgsin$\theta$ is pulling down the box to down .

Hence, in order to push the box , applied force F as shown in figure is parallel to force component mgsin$\theta$ and in opposite direction to the force component mgsin$\theta$ . This direction is also parallel to inclined plane.