Class 8 Science

# Friction

## Extra Questions

### Multiple Choice Questions

Question 1: Which of the following uses spikes in shoes?

1. Lawyer
2. Doctor
3. Rugby player
4. Painter

Question 2: Mobil oil is used in scooters and bikes for which purpose?

1. As fuel
2. For reducing friction
3. For increasing friction
4. None of the above

Question 3: Tyres of which vehicles are biggest treads among the following?

1. Race car
2. Car
3. Motorbike
4. Excavator

Question 4: Which of the following is used in powdered form as lubricant?

1. Graphite
2. Chalk
3. Salt
4. Sugar

Question 5: Increasing friction is necessary for which of the following?

1. Free wheel of bicycle
2. Bicycle handle bar
3. Chain of bicycle
4. Ball bearing in front wheel

Question 6: Which of the following surfaces will offer the least friction?

1. Vinyl floor
2. Plywood
3. Plastic
4. Ice

Question 7: Least amount of friction is required in which of the following sports?

1. Car Race
2. Football
3. Ice Skating
4. Tug of war

### Very Short Answer Type Questions

Question 1: What is friction?

Answer: The force created due to relative movement between two surfaces is called friction.

Question 2: What is static friction?

Answer: The minimum amount of force that is required to overcome the force of friction is called static friction.

Question 3: What is sliding friction?

Answer: Once an object starts moving on a surface, some force is required to keep the object moving. The minimum force that is required to keep a moving object in motion at a constant speed is called sliding friction.

Question 4: What is rolling friction?

Answer: When an object rolls over a surface, the friction created is called rolling friction.

Question 5: Arrange different types of friction in descending order?

Answer: Static friction > Sliding friction > Rolling friction

Question 6: What is fluid friction?

Answer: Friction due to a fluid is called fluid friction or drag.

Question 7: What is a streamlined shape?

Answer: A shape which is wide in middle and tapered at ends is called a streamlined shape.