Q: All surfaces are smooth. The acceleration of mass *m* relative to the wedge is

(a) *g* sin θ

(b) *g* sinθ + *a* cos θ

(c) *g* sin θ – *a* cos θ

(d) *a* cos θ

Ans: (b)

Sol: By applying pseudo force

Downward component of force is

F = m *g* sinθ + m *a* cos θ

acceleration of mass *m* relative to the wedge is

a’ = F/m

a’= *g* sinθ + *a* cos θ