The force and pressure chapter is related to class 8th. What does one mean by force and pressure? What are different types of force?
Force and Pressure:
Meaning
- When we pull or push any item, then it is called force.
- Or, when there is any interaction between objects, it develops force.
- The force’s strength is always called magnitude.
Types
Contact force:
When we touch any item, then it moves. Well, it is known as contact force.
For example, Pulling, Lifting, Kicking and Pushing.
Muscular force:
When we apply force with the help of our muscles, it is called muscular force.
For example, Magnetic force gravitational force.
Nuclear forces:
- It is the force that will act between all the particles.
- The particles consist of protons, neutrons, and many others.
Non-contact forces:
- The force which does not make any contact.
- LIKE: Magnetic force, gravitational force, an electrostatic force.
Pressure
It is the per-unit force over an area.
- The formula for pressure: Force/Area.
- The unit of force is Pascal.
Distribution (Pressure):
- The force which acts on the smaller area has more pressure.
- Example: Porters, sharper knife
Learning Videos for 8th Grade Science - Force and Pressure
Force and Pressure Sample Questions for Class 8
Question 1
Pressure exerted by a body on a surface is
A. Force × area
B. Force ÷ area
C. Area ÷ force
D. Force ÷ volume
Question 2
Two magnets A & B are placed with like poles having one above another. What will happen?
A. A will stuck to B
B. A will remain as shown in the figure
C. A will move side ways
D. Can't say
Question 3
The magnetic force between a magnet and a magnetic substance can cause:
A. change of state
B. change of shape
C. change of size
D. change of property
Question 4
The diagram shows an object hanging from a string. Select the correct statement about the diagram.
A. The object does not fall because there is no gravity
B. The object does not fall because there is friction between the object and the string
C. The object does not fall because a magnetic force is acting on it
D. The object does not fall because the string is exerting a force against the earth's gravity
Question 5
Gautam finds it difficult to walk on an icy surface because _______.
A. Gravitational force exerted on an icy surface is less than on other surface
B. Gravitational force exerted on an icy surface is greater than on other surfaces
C. There is little or no friction between his shoes and the ice
D. There is too much friction between his shoes and the ice