Question

when angle of friction is 45 degrees then coefficient of friction is ​

Answer 1

Answer:

The friction coefficient cannot be 1. Only less than 1. So, in a real instance, a body will never start going down freely on an inclined plane of 45 degree.

Answer 2

Answer:

The object lying on the incline with a 45 degrees angle is going down with the constant velocity.

The force acting down ,parallel ,to the incline =F[d]=mg sin 45

The force of reaction perpendicular to the plane =R= mg cos 45

The force due to friction =F[f]= uR= u mg cos 45

If there is constant velocity then the resultant acceleration is zero

That is the resultant force =F[r]=0

F[r] =F[d] -F[f]=0

F[r]= mg sin 45 -u mg cos 45 =0

Then u=1 ,this means the object cannot move and the constant velocity is zero and the object does not move at all .

So the object cannot have a zero acceleration but must be decelerating.

The equation should read

F[d]-F[f]=ma