Class 8 Science


Extra Questions

Multiple Choice Questions

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

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

Answer: (c) Rugby player

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

Answer: (b) For reducing friction

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

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

Answer: (d) Excavator

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

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

Answer: (a) Graphite

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

Answer: (b) Bicycle handle bar

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

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

Answer: (d) 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

Answer: (c) Ice Skating

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.