Question

Force resisting the upward motion of a body on an inclined plane is given by (alpha – the angle of inclination, W- the weight of the body).

(a) F = W×sin(alpha)

(b) F = W×cosec(alpha)

(c) F = W×sec(alpha)

(d) F = W×cos(alpha)

The question was posed to me during an interview.

I would like to ask this question from Dynamics topic in portion Dynamics of Electrical Drives of Electric Drives

Answer 1

Right option is (a) F = W×sin(alpha)

The explanation: When a body is moving upward on an inclined plane its weight can be resolved in two perpendicular components that are W×sin(alpha) and W×cos(alpha). W×cos(alpha) is the component that is opposite to normal of the inclined plane and W×sin(alpha) is the component that opposes the upward motion of the body.