Force and Pressure class 8 questions and answers: Science Class 8 chapter 8 question answer
| Textbook | Ncert |
| Class | Class 8 |
| Subject | Science |
| Chapter | Chapter 8 |
| Chapter Name | Force and Pressure ncert solutions |
| Category | Ncert Solutions |
| Medium | English |
Are you looking for Class 8 Science chapter 8 question answer? Now you can download ncert solutions for class 8 science chapter 8 pdf from here.
Question 1: Give two examples each of situations in which you push or pull to change the state of motion of objects.
Answer 1: Examples of situations in which you push or pull to change the state of motion of objects are:
Push Examples:
- Pushing a Swing – When you push a swing, it starts moving forward and backward.
- Pushing a Shopping Cart – When you push a shopping cart, it starts moving forward.
Pull Examples:
- Pulling a Door Handle – When you pull a door handle, the door opens towards you.
- Pulling a Rope – When you pull a rope in a tug-of-war game, the rope moves toward you.
Question 2: Give two examples of situations in which applied force causes a change in the shape of an object.
Answer 2: The forces which change the shape of an object are as follows:
- Stretching a Rubber Band – When you pull a rubber band, it stretches and changes shape.
- Pressing a Clay Ball – When you press a ball of clay with your hands, it gets deformed and changes 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 3:
- To draw water from a well, we have to pull at the rope.
- A charged body attracts an uncharged body towards it.
- To move a loaded trolley, we have to pull or push it.
- The north pole of a magnet repels the north pole of another magnet.
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 4:
- (a) To stretch the bow, the archer applies a force that causes a change in its shape.
- (b) The force applied by the archer to stretch the bow is an example of muscular force.
- (c) The type of force responsible for a change in the state of motion of the arrow is an example of a contact force.
- (d) While the arrow moves towards its target, the forces acting on it are due to gravity and that due to friction of air.
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 5:
(a) When squeezing a piece of lemon between the fingers, the fingers act as the agent applying force on the lemon. This force changes the shape of the lemon and causes the juice to be extracted. The type of force involved is muscular force.
(b) While taking out paste from a toothpaste tube, the hand applies force on the toothpaste tube. This force deforms the tube, pushing the paste out through the nozzle. The force involved is muscular force.
(c) A load suspended from a spring while its other end is fixed to a wall experiences force due to the load acting on the spring. This force stretches the spring, causing it to elongate. The type of force here is gravitational force acting downward due to the weight of the load.
(d) When an athlete makes a high jump to clear a bar, the legs of the athlete exert force on the ground to push the body upwards. This force helps the athlete gain height and clear the bar. The force involved is muscular force, which enables the jump, and gravitational force, which pulls the athlete back to the ground.
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 6: A blacksmith uses their muscular force while hammering a hot piece of iron. The muscular force changes the shape of the iron so that it can be given the desired shape.
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 7: An inflated balloon becomes charged when it is rubbed against a wall after being rubbed with synthetic fabric. The balloon attaches to the wall because a charged body attracts an uncharged body. The electrostatic force is the force that exists between the charged balloon and the wall.
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 8: In this case, muscular force is acting in upward direction and the force of gravity is acting in downward direction. Both forces are acting in opposite directions to each other and hence nullify the effect of each other. Due to this, there is no change in the state of motion of the bucket.
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 9: The forces that draw the rocket towards the earth include gravity and friction caused by the earth’s atmosphere, which prevents it from moving in the direction that it is intended to.
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 10: (d) atmospheric pressure
Explanation: When we press the rubber bulb of the dropper, the air inside escapes as bubbles. When we release the pressure, the air inside creates a vacuum, and the atmospheric pressure outside pushes water into the dropper, causing it to rise. This phenomenon occurs due to the atmospheric pressure acting on the surface of the water.