A student pushes a rectangular wooden door of width 0.90 m about its vertical hinge line.
PHYSICS · Multi-part · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
A student pushes a rectangular wooden door of width 0.90 m about its vertical hinge line.
(a) Define the term "lever arm" in the context of rotational motion.
(b) With the help of a clearly labelled sketch, explain why the rotational effect of the push depends on the perpendicular distance between the hinge line and the line of action of the force rather than on the straight-line distance between the hinge and the point of application.
(c) Two forces of equal magnitude act at the same point on the door. One acts normal to the door surface, while the other makes an angle of 60∘ with the normal. Without performing any numerical calculation, state which force produces the larger moment about the hinge and give a brief reason for your answer.