give reason fo the following<br /><br />please do this class 8 science friction
Answers
Q) Give reasons :-
(e) Ball bearings are used in machines
Ball bearings are used in machines to reduce Friction in moving parts of machine and make it easier to carry the load
(f) Tyres of vehicles need to be changed regularly.
Over the time when we keep using the Tyre it gets damaged and rough, which reduces the friction, this may cause the car to slip and cause an accident. To prevent this tyres need to be changed regularly
(g) Machines parts are frequently oiled or greased.
To reduce the friction and make machines work and function smoothly, they are greased or oiled frequently,
(h) Sports cars, airplanes and boats are designed to have a streamlined shape.
The streamlined shape in them helps to cut, and go opposite to the frictional force in air and to move forward with great speed.
(i) Metal chains are wrapped on tyres when they run on icy roads.
Icy roads are smooth in nature and they reduce friction, if we wrap a metal chain on the tyres, it will increase the friction and grip of tyres which will help the car to stop on applying brakes.
(j) Rollers are used for transporting luggage.
Rolling friction is easier as it reduces friction, that's why we use rollers for transporting luggage instead of dragging them.
Given Problem:
Given Reasons.
Answer:
★Friction:
Friction is force which formed when two surfaces rub against each other.
Now Give reasons:
★Ball bearings are used in machines:
Yes, Ball bearings are used in machines,because bearing is lubricant of friction,it reduce the friction.So,every part of machine move easily.
★Tyres of vehicles need to be changed regularly:
Yes, Tyres of vehicles need to be changed regularly.Because,Usually we apply brake on road and get worn of due to friction they become more smoother.These tyres need to be changed regularly.
★Machines parts are frequently oiled or greased:
Yes, Machine's parts are frequently oiled or greased Because we know that Oil and greased are best lubricant of friction. Oil & gearse help to reduce friction.
★Sports cars, airplanes and boats are designed to have a streamlined shape:
Yes, They have streamlined shape to cut the air and go to opposite side of air. As we know areoplane can fly in the opposite side of air That the areoplane's streamlined shape help that to fly in the opposite side.
★Metal chains are wrapped on tyres when they run on icy roads:
Yes, Because the smooth or icy roads help to reduces the friction that is When we apply breaks the vehicle does not stops,for increase friction the iron chains are wrapped on the tyres of trucks in icy areas.
★Rollers are used for transporting luggage:
Yes,Rollers are used for transporting luggage because rollers help to reduce friction and help to roll the transporting luggage.