Question 1:
difficultA block is kept on the frictionless inclined surface with angle of inclination . The incline is given an acceleration a to keep the block stationary w.r.t incline plane. Then a is equal to
Taking incline plane as frame of reference, Pseudo force ma act towards right.
component of Pseudo force up the incline is m.a.cos α which is balanced by m.g.sin α. so,
m.a.cos α = m.g.sin α
⇒a= g tan α