Guest

A time-varying force F=5N is applied on the block kept on a rough surface. Mass of the block is 10kg, coefficient of the static and kinetic friction between the block and the horizontal surface are 0.3 and 0.2 respectively. Take g=10m/s^2. Find the time at which slipping starts between blocks and the surface beneath it. (A) 3s (B) 4s (C) 5s (D) 6s

A time-varying force F=5N is applied on the block kept on a rough surface. Mass of the block is 10kg, coefficient of the static and kinetic friction between the block and the horizontal surface are 0.3 and 0.2 respectively. Take g=10m/s^2. Find the time at which slipping starts between blocks and the surface beneath it.
 
(A) 3s
(B) 4s
(C) 5s
(D) 6s

Question Image
Grade:11

1 Answers

Arun
25750 Points
3 years ago
Assume no friction, the motion of the block will be in the direction of applied force. The friction opposes relative motion between two surfaces. The direction of friction will be opposite to relative motion, i.e., in leftward direction.
Now let us find the maximum friction force.
max
​ 
 =f 
lim
​ 
 =μ 
s
​ 
 N=0.2×1×10=2N
a. If F=1.0N
If the block is at rest friction acting on the block, f=F= 0.1N.
As f
lim
​ 
 , hence, friction will be of static nature and acceleration of the block will be zero.
b. If F= 0.2 N
Here the applied force equals limiting friction. The block is on the verge of slipping.
or f=f 
lim
​ 
 =2.0N
c. If F=2.5N
Here the applied force is greater then the magnitude of the maximum nature of static friction. The nature of friction between the block and ground is of kinetic nature.
or f=f 
k
​ 
 =μ 
k
​ 
 N=0.15×1×1.5N

Think You Can Provide A Better Answer ?

ASK QUESTION

Get your questions answered by the expert for free