PhysicsLens.com

Vectors at Angles

Explore how angle changes affect force components, moments & work

30°
10 kg

Weight mg resolves into a component along the slope (mg sinθ, drives motion) and perpendicular to it (mg cosθ, balanced by the normal force). The slope is frictionless.

Weight (mg) Parallel & normal components
mg sinθ
–
mg cosθ (Normal)
–
Acceleration down the slope
–
90°
50 N
0.25 m

Moment (torque) about the nut = F × r × sinθ. Only the component of force perpendicular to the wrench contributes; a force applied along the handle (θ = 0° or 180°) produces zero turning effect.

Applied force Perp. & along-wrench components
Perpendicular comp. (F sinθ)
–
Along-wrench comp. (F cosθ)
–
Moment, M = F·r·sinθ
–
30°
40 N
5 m

Only the component of force along the direction of motion does work: W = F·d·cosθ. At θ = 90° the force does no work; beyond 90° it does negative work.

Applied force Component along d Displacement
Component along d (F cosθ)
–
Perpendicular comp.
–
Work done, W = F·d·cosθ
–