FrictionMedium
Question
In the given figure the coefficient of friction between 4kg and 5 kg blocks is 0.2 and between 5 kg block and ground is 0.1 respectively. Choose the correct statements


Options
A.Minimum force needed to cause system to move is 17 N
B.When force is 4N static friction at all surfaces is 4N to keep system at rest
C.Maximum acceleration of 4kg block is 2m/s2
D.Slipping between 4kg and 5 kg blocks start when F is > 17N
Solution
So block ′Q′ is moving due to force while block ′P′ due to friction.
Friction direction on both +Q blocks as shown.

First block ′Q′ will move and P will move with ′Q′ so by FBD taking ′P′ and ′Q′ as system
F − 9 = 0 ⇒ F = 9 N
When applied force is 4 N then FBD

4 kg block is moving due to friction and maximum friction force is 8 N.
So acceleration = 8/4 = 2/m/s2 - amax.
Slipping will start at when Q has +ve acceleration equal to maximum acceleration of P i.e. 2 m/s2.
F − 17 = 5 × 2 ⇒ F = 27 N.
Friction direction on both +Q blocks as shown.

First block ′Q′ will move and P will move with ′Q′ so by FBD taking ′P′ and ′Q′ as system
F − 9 = 0 ⇒ F = 9 N
When applied force is 4 N then FBD

4 kg block is moving due to friction and maximum friction force is 8 N.
So acceleration = 8/4 = 2/m/s2 - amax.
Slipping will start at when Q has +ve acceleration equal to maximum acceleration of P i.e. 2 m/s2.
F − 17 = 5 × 2 ⇒ F = 27 N.
Create a free account to view solution
View Solution FreeMore Friction Questions
A solid cube of mass 5 kg is placed on a rough horizontal surface, in xy-plane as shown. The friction coefficient betwee...In the given figure the value(s) of mass m for which the 100 kg block remains in static equilibrium is (g = 10 m/s2)...Starting from rest a body slides down a 45o inclined plane in twice the time it takes to slide down the same distance in...Car is accelerating with acceleration = 20 m/s2. A box of mass m = 10 kg that is placed inside the car, it is put in con...(i) From the figure shown, find out acceleration of 3 kg block....