Question

A 24-N block rests on a horizontal surface. The coefficients of static and kinetic friction between the surface and the block are ?s=0.76 and ?k=0.34. A horizontal string is attached to the block and a constant tension T is maintained in the string.

blem 5-23a: A 24 N block rests on a horizontal surface. The coefficients of static and kinetic friction between the surface and the block are us=0.76 and μk=0.34. A horizontal string is attached to the block and a constant tension T is maintained in the s What is the maximum force allowed due to static friction? Submit Answer Tries 0/5 Tries o/s What is the force of friction acting on the block if T = 15.73 N? i: the force of fricdion aci Submit Answer Tries 0/5 What is the force of friction acting on the block if T = 38.39 N?

Answer 1

The maximum static friction is μs*N where N = m*g

So max f = 0.76*24N = 18.24 N

If you pull with a tension less than this the block will not begin to move

So the frictional force just equals the tension = 15.73 N

Now the Tension has overcome static friction and the block is moving
Here the frictional force = μk*N = 0.34*24N = 8.16 N and the block is accelerating