Question

C. Tick() the correct option.
1. Suppose your writing desk is tilted to a position where a book kept on it just
starts sliding down. The figure, showing the correct direction of frictional force
acting on it, is-
​

Answer 1

Answer:

c one friction where book is coming downwards or sliding down.

Answer 2

Required Answer:

Friction is a type of force which opposes the relative movement between two surfaces in contact. And it is always parallel to the surface in contact.

In this case, the two surfaces in contact, is the surface of the book and the desk which is little tilted. So due to gravitational force, the book will slide down. But the friction will oppose this relative motion is opposite direction i.e upwards.

✏️ Refer to the attachment..$.$

Explore more !!

Let's know better about the frictional force:

• Frictional Force is more for rough surfaces and less for smooth surfaces.
• They always act parallel to the surface.
• Friction causes the body not to much distance and stop after a while (due to above reason).
• It is caused due to the irregularities.
• Type of friction - Static friction, Sliding force, Rolling friction, Air resistance, Viscous friction.
• Frictional Force increases if the two surfaces are pressed harder.
• It increases with the weight of the body.
• It does not depends upon the area of contact but it depends upon the nature of the surfaces.

And we are done !!