Q.2 Write two ways in which friction can be useful and two ways it can be a nuisance.
Answers
Answer:
Explanation: advantages:
1.friction enables us to write.
2.it enable the movement of vehicles and humans.
nuisance:
1.parts of machines wear out due to friction.
2.causes wear and tear
Answer:
Friction is the force that resists motion when the surface of one object comes in contact with the surface of another. It is also defined as the resistance offered by the surfaces that are in contact with each other when they move over each other.
Examples
We see friction in our day to day activities. Following are the ten examples of friction in daily life:
Walking –We can walk only if we apply frictional force. Friction is what holds your shoe to the ground. The friction present on the ice is very little, this is the reason why it is hard to walk on the slippery surface of the ice.
Writing – A frictional force is created when the tip of the pen comes in contact with the surface of the paper. Rolling friction is what comes into play while writing with a ballpoint pen while sliding friction arises when one writes with a pencil.
Skating – A thin film of water under the blade is necessary to make the skate slide. The heat generated by the skate blade rubbing against the surface of ice causes some of the ice to melt right below the blade where the skater glides over the ice. This water acts as a lubricant reducing friction.
Lighting a matchstick – When the head of the matchstick is rubbed against a rough surface, heat is generated and this heat converts red phosphorous to white phosphorous. White phosphorous is highly inflammable and the match stick ignites. Sometimes, matchsticks fail to ignite due to the presence of water. Water lowers friction.