Case Study Questions for Class 8 Science Chapter 12 Friction

Case Study Questions for Class 8 Science Chapter 12 Friction

Here we are providing case study questions for CBSE Class 8 Science Chapter 12 Friction.

Case Study Questions

Question 1:

Friction is a force between two surfaces that are sliding, or trying to slide, across each other. Friction always works in the direction opposite to the direction in which the object is moving, or trying to move. It always slows a moving object down.

Friction also produces heat. If you rub your hands together quickly, you will feel them get warmer. Friction can be a useful force because it prevents our shoes slipping on the pavement when we walk and stops car tyres skidding on the road. When you walk, friction is caused between the tread on shoes and the ground. This friction acts to grip the ground and prevent sliding. Sometimes we want to reduce friction. For example, we use oil to reduce the friction between the moving parts inside a car engine. In many machines, friction is reduced by using ball bearings. The reduced friction means there is less wear on the moving parts and less heat produced.

i) When does friction arise?
ii) Why should we apply oil on the hinges of the door?
iii) Gymnasts apply some coarse substance on their hands. Why?
iv) Explain why sportsmen use shoes with spikes.

Answers

i) Friction arises when the irregularities of the two surfaces interlock.

ii) Oils are one of the best lubricants and applying them on the door hinges reduces friction and eases functioning.

iii) Gymnasts apply the coarse substance on their hands to increase friction for a better grip.

iv) It is done to provide the shoes better grip on the ground.