FrictionHard

Question

A plank of mass m1 = 8 kg with a bar of mass m2 = 2 kg placed on its rough surface, lie on a smooth floor of elevator ascending with an acceleration g/4. The coefficient of friction is μ = 1/5 between m1 and m2. A horizontal force F = 30 N is applied to the plank. Then the acceleration of bar and the plank in the reference frame of elevator are:

Options

A.3.5 m/s2, 5 m/s2
B.5 m/s2, 50/8 m/s2
C.2.5 m/s2, 25/8 m/s2
D.4.5 m/s2, 4.5m/s2

Solution

(C)     Solving from the frame of elevator
geff. = g + g/4 = 12.5

f = × 2 × 12.5 = 5N
a2 = = 2.5 m/s2
a1 = m/sec2

Create a free account to view solution

View Solution Free
Topic: Friction·Practice all Friction questions

More Friction Questions

A uniform rope so lies on a table that part of it lays over. The rope begins to slide when the length of hanging part is...A block of metal weighing 2 kg is resting on a frictionless plane. It is struck by a jet releasing water at a rate of 1 ...A uniform solid sphere rolls on a horizontal surface at 20 ms-1. It then rolls up and incline having an angle of inclina...A wooden block of mass m resting on a rough horizontal table (coefficient of friction = μ) is pulled by a force F a...A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizontal rope tied to a ...