Question

when an object slides down an inclined plane then coefficent of friction will be?
(a) Cos Ф
(b) Sin Ф
(c) Tan Ф
(d) None

Answer 1

It will tan theta dear.....

Answer 2

There are three forces acting on the object:-

1️⃣ The force of gravity – mg

2️⃣ The normal force – N

3️⃣ The frictional force – fk

✔️According to the Newton’s First Law of motion, if the object moves at constant velocity then net force on an object is zero.

✔️Therefore, the sum of the projections of the forces along each axis is zero and the Newton’s equations of motion are:-

1️⃣Y – axis :    N – m*g*cos(α) = 0

2️⃣X – axis :    – fk + m*g*sin(α) = 0

Let’s use the fact that:

✔️fk = μk*N

Hence,

– μk*m*g*cos(α) + m*g*sin(α) = 0

Finally,

μk = tan(α)

So....

Correct option: C