Question

a block of mass 1kg is sliding on a rough surface platform with velocity 2m/s an external force 1N acting on the block .Find the direction of kinetic friction​

Answer 1

Answer:

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.

f

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<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