Class 8 Science Chapter 8 Force And Pressure Very Short Answer Type Questions
Question 1. Where do we apply a force while walking?
Answer: We apply a force on the ground while walking, and the ground applies a reaction force on our foot, due to which we can move forward.
Question 2. Does the palm apply any force on the ball when we place our palm in front of a moving ball?
Answer: Yes, when we place our palm in front of a moving ball, then the palm applies a force on the moving ball and stops it.
Question 3. Name an activity that does not involve any pushing force.
Answer: When a person swims freestyle, he is pulling themselves forward in the water.
Question 4. A ball of dough is rolled into a flat chapati. Name the force exerted to change the shape of the dough.
Answer: The shape of the dough is changed due to the muscular force applied by the hand.
Question 5. In ‘tug of war’, when two teams pull equally hard, what happens?
Answer: In ‘tug of war’, when two teams pull equally hard, then the rope does not move in any direction.
Question 6. A girl is pushing a box towards the East. In which direction should her friend push the box, so that it moves faster in the same direction?
Answer: Her friend should push the box towards the East direction, so that it will start moving faster towards the East because the magnitude of force increases.
Question 7. During dry weather, clothes made of synthetic fibre often stick to the skin. Which type of force is responsible for this phenomenon?
Answer: The electrostatic force starts working between the cloth made of synthetic fibre and sticks to the skin.
Question 8. Two thermocol balls are held close to each other, but they move away from each other when they are released. Name the force which might be responsible for this phenomenon. Explain.
Answer: This is an electrostatic force which is created due to the rubbing, and since the same charges are induced on two balls, they move away from each other.
Question 9. While sifting grains, small pieces fall. Which force pulls them down?
Answer: It is the force of gravity that is responsible for the grains to fall.
Question 10. Does the force of gravity act on dust particles?
Answer: Yes, the force of gravity acts on the dust particles.
Question 11. A gas-filled balloon moves up. Is the upward force acting on it larger or smaller than the force of gravity?
Answer: The upward force will be greater than the force of gravity, then the balloon will be able to lift against this gravitational force.
Question 12. Fruits detached from a tree fall due to the force of gravity. We know that a force arises due to the interaction between two objects. Name the objects interacting in this case.
Answer: The interacting objects in this case are: Earth and fruit. Earth applies a force of gravity on the fruit towards its centre, so the fruit falls.
Question 13. Rahul is pushing a magnet along his table when some paper clips on his table suddenly move. In which direction does the force act on the paper clips?
Answer: As the magnet will attract the paper clips, the force acting on them will be towards the magnet.
Question 14. Under which circumstances, a person not experience any gravitational force?
Answer: A person who is in a space that is too far away from Earth’s gravitational force will not suffer any gravitational force.
Question 15. An astronaut travels from Earth to the moon. How does his weight and mass change?
Answer: The Mass of an object remains constant at all places, so the mass of the astronaut will not change. The weight of an object depends on the gravity; on the moon, gravity is less than on Earth, so the weight of an astronaut will decrease.
Question 16. Have you ever wondered what makes an object slow down or go faster or change its direction of motion?
Answer: Force makes an object slow down or go faster, or change its direction of motion.
Question 17. Paheli remembers that a magnet attracts a piece of iron towards it. Is attraction also a pull? What about repulsion between similar poles of two magnets? Is it a pull or a push?
Answer: The Attraction or repulsion between the poles of a magnet can be seen as another form of pull or push.
Question 18. Does it mean that the net force on an object is zero if the two forces acting on it in opposite directions are equal?
Answer: Yes, when two forces of equal magnitude act in opposite directions, the net force is zero on that body.
Question 19. Boojho has seen children competing with one another in moving a rubber tyre or a ring by pushing it. Why does the speed of the tyre or ring increase whenever it is pushed?
Answer: With every push, they are applying a little more force on the moving tyre in the direction of motion. Hence, the speed of the tyre increases continuously.
Question 20. Does the application of a force always result in a change in the state of motion of the object?
Answer: No, sometimes a heavy material may not move at all, even if you apply the maximum force that you can exert.
Example: When you try to push a wall, no effect of force is observed.