Question

A student places a rectangular rubber eraser on a leather-bound book, and begins to tilt the book. If the coefficient of friction between leather and rubber is 0.61, at what angle will the eraser first start to slide?

Help me plz

Answer 1

31.4°

Step-by-step explanation:

The force that exists between the eraser and the block is known as the frictional force.

Frictional force is a force of opposition expressed as

Ff = nR where

Ff is the frictional force

n is the coefficient of friction

R is the normal reaction.

If the body is placed on an inclined plane, Ff = Fm = Wsintheta

Fm is the moving force acting along the plane.

R = W = Wcostheta

from the formula

n = Ff/R

n = Wsintheta/Wcostheta

n = sintheta/costheta

n = tantheta

0.61 = tantheta

theta = tan^-1(0.61)

theta = 31.4°

Answer 2

• 31º.

Step-by-step explanation:

Using a free body diagram, it is proved that when the object starts to slide, the tangent of the angle of inclination is equal to the coefficient of static friction:

`\mu_s=tan(\beta )`

Hence, you can use that formula directly:

`0.61=tan(\beta )\\ \\ \beta =arctan(0.61)\\ \\ \beta =31.38\º`

Rounding to the nearest degree that is 31º.