Question

A lift is moving up with acceleration a .

(a) Velocity of bolt immediately after release in earth frame .

(b) Acceleration of bolt immediately after release in earth frame .

(c) Velocity of bolt immediately after release in lift frame .

(d) Acceleration of bolt immediately after release in lift frame .

Options :-
(p) (g+a) downward

(q) (g+a) upward

(r) g

(s) 0

(t) 'AT ' in upward direction​

Answer 1

Answer:

lift is moving upward with acceleration 2m/s². so, lift is an non-inertial frame of reference. but we know, we can't apply Newtonian equation in case of non-inertial frame. to make it inertial frame, apply pseudo force just opposite it and equal in magnitude.

so, pseudo force , P = m(2)

and weight of bolt, F = m(g)

then, net force = ma = mg + m2 =>a = (g + 2)

so, net acceleration acting on bolt, a = (g + 2) = 12m/s²

given, height of lift , h = 6m

initial velocity of bolt , u = 0

then, h = ut + 1/2 at²

or, 6 = 0 + 1/2 × (12) × t²

or, 6 = 6t² => t = 1

hence, time taken by bolt to hiy the floor of the lift is 1sec.