CBSE Science Class 8
Friction
Friction - Chapter Wise CBSE Solved Question and Answer Based On NCERT
Points To Remember:
- Friction is the "evil" of all motion. No matter which direction something moves in, friction pulls it the other way
- Friction is caused by the irregularities on the two surfaces in contact
- Friction depends on nature of surfaces in contact
- Friction depends on how hard the two surfaces press together.
- Static friction comes into play when we try to move an object at rest
- Sliding friction comes into play when an object is sliding over another
- Friction is important for many of our activities like striking of matchstick, fixing of nail in the wall etc.
- Friction can be increased by making a surface rough
- Friction can be reduced by using lubricants, in many machines friction is reduced by using ball bearings
- Sliding friction is smaller than static friction and rolling friction is smaller than sliding friction
- The sole of the shoes and tyres of vehicles are treated to increase friction
