Force and Pressure Class 8 Extra Questions Science Chapter 11

Force and Pressure Class 8 Extra Questions Science Chapter 11

Question 1.
What is the name of the instrument used to measure atmospheric pressure?
Barometer

Question 2.
Give two examples of contact force.

• Muscular force
• Force of friction

Question 3.
What kind of force is an electrostatic force?
Non-contact force

Question 4.
Name the force due to which every object falls on earth.
Gravitational force

Question 5.
What kind of force is friction?
Contact force

Question 6.
What is a force?
A push or pull on an object is called force.

Question 7.
What is the SI unit of pressure?
Pascal (Pa)

Question 8.
At least how many objects are needed to apply a force?
At least two objects are needed to apply a force.

Question 9.
What is muscular force?
The force resulting due to the action of muscles is known as muscular force.

Question 10.
What is contact force?
The force that can be applied only when it is in contact with an object is called contact force.

Question 11.
What is the similarity between electrostatic and magnetic forces?

• Both are non-contact forces.
• Both are attractive as well as repulsive forces.

Question 12.
Define the different types of forces.
Depending on this, forces can be classified as contact and non-contact forces.

• Contact forces: When force is applied on an object by direct or indirect physical contact the applied force is called contact force. Muscular and frictional force are example of contact force.
• Muscular force: The force resulting due to the action of muscles is known as the muscular force.
• Frictional force: The force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
•  Non-contact forces: When a force is applied to an object by another body that is not in direct contact with it is called non-contact force. Gravitational, magnetic and electrostatic force are example of non-contact force.
• Gravitational force: The attractive force of the earth which acts upon all the objects is known as the force of gravity or just gravity.
• Electrostatic force: The force exerted by a charged body on another charged or uncharged 1 body is known as electrostatic force.
• Magnetic force: The force exerted between a magnet and other magnet or magnetic material is known as magnetic force.