Welcome to the Chapter 11 - Force and Pressure, Class 8 Science NCERT Solutions page. Here, we provide detailed question answers for Chapter 11 - Force and Pressure. The page is designed to help students gain a thorough understanding of the concepts related to natural resources, their classification, and sustainable development.
Our solutions explain each answer in a simple and comprehensive way, making it easier for students to grasp key topics Force and Pressure and excel in their exams. By going through these Force and Pressure question answers, you can strengthen your foundation and improve your performance in Class 8 Science. Whether you’re revising or preparing for tests, this chapter-wise guide will serve as an invaluable resource.
Force is simple called as push or pull.
Examples of push:
Examples of pull force are as follows:
(d) An atmospheric pressure
It is because, 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. So, rise of the water in the dropper is due to the atmospheric pressure. When all the air escapes from the nozzle, then the atmospheric pressure, act on water, forces to fill the dropper.
By applying force, shape of the object got changed. Some examples are as follows:
(a) Pull
Pull or push is simply called as force. To draw water from a well, we have to pull whereas we have to apply push force on bucket to throw it in the well.
(b) Attracts
When a charged body attracts another charged or uncharged body towards it, is called as the electrostatic force of attraction.
(c) Push
If we want to change in the direction of trolley, we have to apply either push force or pull force on it. In the pull force, the direction changes in object is same to the applying force.
(d) Repels
Magnet have two poles: North and South. Same pole repels each other whereas opposite poles of magnet attracts each other.
(a) Shape
Applied force can change the shape and the direction of the object. So, when we stretch a bow, pull force is applied on it, so its shape is changed.
(b) Muscular
Stretching of bow is the example of a contact force. In this, muscular force is applied on it. With the help of muscular force, we stretch the bow.
(c) Contact
Contact force are the forces that act between two objects that are physically touching each other. Here, we touch bow physically, this is an example of contact forces.
(d) Gravity, friction
The friction force is applied by the air is known as the drag force. When arrow moves towards the target, earth attracts the arrow towards itself due to gravity and the frictional force of air also come into play.
When a blacksmith hammers a hot piece of iron, he uses its muscular force on the hot piece of iron. This is the example of contact force also. By applying muscular force, blacksmith is able to change in the shape of the hot iron piece.
When an inflated balloon is rubbed with a piece of synthetic cloth, then it becomes charged. The balloon sticks to the wall because of the attractional force present between them. When a charged body attracts an charged or uncharged body towards itself then it is known as electrostatic force of attraction. Hence, the balloon sticks on the wall due to the presence of electrostatic force of attraction between the balloon and the wall.
Here, muscular force is acting on the plastic bucket containing water held above the ground level. Muscular force is applied in the opposite direction of gravity; here which pulls the bucket towards the ground. Here both muscular and gravity are equal in magnitude. So, both the forces cancel out each other. Here the net force on the bucket is zero. Hence there is no change in the state of the motion of the bucket.
When a rocket is fired upwards to launch a satellite in its orbit, then the force of gravity is acting on it. The force of gravity pulls the rocket towards the earth but the force of friction which is due to the earth’s atmosphere, opposes its motion.