Question

When opening a door, you push on it perpendicularly with a force of 46.0 N at a distance of 0.740 m from the hinges. 1. What torque (in N·m) are you exerting relative to the hinges?2. Does it matter if you push at the same height as the hinges? There is only one pair of hinges.

Answer 1

given,

Force acting perpendicularly to the door = 46 N

distance from the hinge = 0.740 m

we know,

torque = Force x distance

τ = F x r

τ = 46 x 0.740

τ = 34.04 N.m

b) No it does not matter if we push at the same height as the hinges.

now, From the expression we can clearly see that what matters is the perpendicular distance from the point of force application.