Force And Pressure NCERT Solutions for Class 8

Force And Pressure Class 8 is a crucial unit of the science syllabus and students need to be thorough in the concepts the chapter talks about. SimplyAcad has compiled all the NCERT solutions for Class 8 Science Force And Pressure together below. Students can use these solutions to gain in-depth understanding of the chapter and perform better in their coming examinations.

Access the NCERT Solutions for Class 8 Force And Pressure

Question 1.

Give two examples each of the situations in which you push or pull to change the state of motion of objects.
Answer:

(i) Push:

• We close the drawer by pushing.
• We move a wooden box by pushing.

(ii) Pull:

• We draw water from a well by pulling the rope.
• A horse pulls a cart.

Question 2.

Give two examples of situations in which applied force causes a change in the shape of an object.
Answer:

• When we apply force on a rubber band to stretch it.
• When we apply force on clay to change its shape.

Question 3.

Fill in the blanks in the following statements.
(a) To draw water from a well we have to ______ at the rope.
(b) A charged body ______ an uncharged body towards it.
(c) To move a loaded trolley we have to ______ it.
(d) The north pole of a magnet _______ the north pole of another magnet.

Answer:
(a) pull
(b) attracts
(c) push
(d) repels

Question 4.

An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information, fill up the gaps in the following statements using the following terms: muscular, contact, non-contact, gravity, friction, shape, attraction.

(a) To stretch the bow, the archer applies a force that causes a change in its ______.
(b) The force applied by the archer to stretch the bow is an example of ______ force.
(c) The type of force responsible for a change in the state of motion of the arrow is an example of a ______ force.
(d) While the arrow moves towards its target, the forces acting on it are due to _______ and that due to _____ of air.

Answer:
(a) shape
(b) muscular
(c) contact
(d) gravity, friction

Question 5.

In the following situations, identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.
(a) Squeezing a piece of lemon between the fingers to extract its juice.
(b) Taking out paste from a toothpaste tube.
(c) A load suspended from a spring while its other end is on a hook fixed to a wall.
(d) An athlete making a high jump to clear the bar at a certain height.

Answer:
(a) Agent: Fingers, Object: Lemon, Effect of Force: Changes the shape of the lemon.
(b) Agent: Fingers of the person squeezing the tube, Object: Toothpaste tube, Effect of Force: Paste comes out of the tube (change in shape).
(c) Agent: Load suspended, Object: Spring, Effect of Force: Elongation of the spring on suspension of the load (change in shape).
(d) Agent: Muscles of the athlete, Object: Athlete himself, Effect of Force: Changes the state of motion of the athlete.

Question 6.

A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?
Answer:
The force due to hammering causes a change in the shape of the iron, allowing it to be molded into the shape of the required tool.

Question 7.

An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?
Answer:
Electrostatic force.

Question 8.

Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.
Answer:
Forces acting on the bucket are as follows:

(i) Muscular force of arms acting upward.
(ii) Force of gravity acting downward.

Both forces do not bring any change in the state of motion because they act in equal and opposite directions, canceling each other’s effect.

Question 9.

A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.
Answer:
The forces acting when a rocket leaves the launching pad are as follows:

(i) Gravitational force of the earth (downward)
(ii) Frictional force of air (in the opposite direction)

Question 10.

When we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to
(a) pressure of water
(b) gravity of the earth
(c) shape of rubber bulb
(d) atmospheric pressure
Answer:
(d) atmospheric pressure