Question 1 Why is the surface of slide polished to make it smooth? Question 2 Name 2 lubricants? Question 3 Why do we sprinkle fine powder on carrom board? Question 4 Which force gets reduced when two surfaces in contact are polished to make them smooth? Question 5 State one way in which the friction between wheel and axle can be reduced? Question 6 Why does … [Read more...] about Methods of Reducing Friction
Friction
Fluid Friction
Question 1 What are fluids. Give example? Question 2 What is fluid friction? Question 3 What is the special name of frictional force exerted by fluids? Question 4 What is a streamlined shape? Question 5 Explain why a speedboat has a streamlined shape? Question 6 Why are cars, aeroplanes and rockets streamlines? Question 7 Give two examples of drag … [Read more...] about Fluid Friction
Methods of Increasing Friction
Question 1 What is a groove? Question 2 What is a tread? Question 3 Why do gymnasts apply a coarse substance to their hands? Question 4 What is done to increase friction between the tyres and road? Question 5 Why do kabaddi players rub hands with dry soil? Question 6 Why grooves are made in the soles of shoes? Question 7 Explain why sportsmen use shoes with … [Read more...] about Methods of Increasing Friction
Disadvantages of Friction
Question 1 What makes the steps of foot over bridges at railway station to wear out slowly? Question 2 Which part wear away first in shoe? Give a reason for your answer? Question 3 Why do brake pads of bicycles have to be replaced quite often? Question 4 A pencil eraser loses tiny pieces of rubber each time you use it. Why does this happen? Question 5 What happen … [Read more...] about Disadvantages of Friction
Advantages of Friction
Question 1 Why is it difficult to move on wet marble floor? Question 2 Why is it difficult to walk properly on a well polished floor? Question 3 What prevents you from slipping every time you take a step forward? Question 4 What enables us to fix nails in a wall and knots to be tied? Question 5 Why does a man slip when he steps on a banana peel thrown on the … [Read more...] about Advantages of Friction