Question

Fill in the following blanks with suitable words : 

(a) Friction always opposes…………..between the surfaces in contact with each other. 

(b) Sliding friction is …………..than the static friction. 

(c) Friction produces……………. 

(d) Friction prevents our foot from…………..over the ground. 

(e) Sprinkling of powder on the carom board………….friction. 

(f) Ball bearings reduce friction because they……………rather than ‘slide. 

(g) The friction when something moves through a liquid or gas is called…… 

(h) Cars and speedboats are………..to reduce drag. 

(i) Shapes that are designed to reduce air resistance are called…………shapes.

(j) Objects which can move quickly through the water have a ………shape. 

(k) The shape of an aeroplane is similar to that of a…………in flight.

Answer 1

(a) Friction always opposes motion between the surfaces in contact with each other 

(b) Sliding friction is less than the static friction. 

(c) Friction produces heat 

(d) Friction prevents our foot from slipping over the ground 

(e) Sprinkling of powder on the carom board reduces friction. 

(f) Ball bearings reduce friction because they roll rather than ‘slide. 

(g) The friction when something moves through a liquid or gas is called drag. 

(h) Cars and speedboats are streamlined to reduce drag. 

(i) Shapes that are designed to reduce air resistance are called streamlined shapes.

(j) Objects which can move quickly through the water have a streamlined shape. 

(k) The shape of an aeroplane is similar to that of a bird in flight.