CBSE Class 8 Science Chapter 8 Force And Pressure SAQs

CBSE Class 8 Science Chapter 8 Force And Pressure Short Answer Type Questions

Question 1. Two people are applying forces on two opposite sides of a moving cart. The cart still moves with the same speed in the same direction. What do you infer about the magnitudes and direction of the forces applied?
Answer: The magnitude of forces will be equal, and they act in opposite directions, so that they cancel each other. We can understand this by using the following

Question 2. A man is pushing a cart down a slope. Suddenly, the cart starts moving faster, and he wants to slow it down. What should he do?

Answer:

The man can do the following things

1. He can start pulling the cart instead of pushing it to balance the downward force due to gravity.
2. He can go to the other side by moving himself very fast in the direction of motion and try to slow down the speed of the cart by giving an opposite force to the moving cart.

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Question 3. A soccer ball flew towards a goalkeeper standing at the goalpost. He tried to grab it, but it slipped from his hands. Describe the action of the force at the point when the goalkeeper grabbed the ball.

Answer:

When the goalkeeper tried to grab the ball coming towards him, the force he applied caused it to change direction. At the same time, the force caused the ball to decrease in its speed. The force applied did not stop the ball from moving or increase its speed.

Question 4. The figure shows a man with a parachute. Name the force that is responsible for his downward motion. Will he come down with the same speed without the parachute?

Answer:

1. The name of the force responsible for the downward motion of the parachute is called force of gravity.
2. No, because the air friction will become less.

Question 5. In the circuit shown in the figure, when the key is closed, the compass needle placed in the match box deflects. Name the force that causes this deflection.

Answer: On closing the switch, the current starts flowing in the wire, and due to this current, a magnetic field is established around the wire, which exerts a magnetic force on the needle, and it gets deflected.

Question 6. Does the force of gravitation exist between two astronauts in space?
Answer: Yes, there will be a gravitational force between the astronauts because every object in the universe, whether small or large, exerts a force on every other object; it is the universal law of gravitation.

Question 7. The figure shows a car stuck to an electromagnet. Name the forces acting on the car. Which one of them is larger?
Answer:

1. The forces working on the object (car) are
2. Force of gravity (downwards)
3. Magnetic force (upwards)

Since the car is moving upwards, so magnetic force due to the electromagnet is greater.