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Test: Force & Pressure - 3 - Class 8 MCQ


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20 Questions MCQ Test - Test: Force & Pressure - 3

Test: Force & Pressure - 3 for Class 8 2024 is part of Class 8 preparation. The Test: Force & Pressure - 3 questions and answers have been prepared according to the Class 8 exam syllabus.The Test: Force & Pressure - 3 MCQs are made for Class 8 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Force & Pressure - 3 below.
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Test: Force & Pressure - 3 - Question 1

The force between two charge bodies is called 

Detailed Solution for Test: Force & Pressure - 3 - Question 1
- The force between two charged bodies arises from their electric charges.
- This interaction is known as electrostatic force.
- It can be attractive or repulsive: like charges repel, while opposite charges attract.
- The strength of this force depends on the amount of charge and the distance between the charges, as described by Coulomb's Law.
- Electrostatic forces are fundamental in understanding electricity, magnetism, and many physical phenomena.
Test: Force & Pressure - 3 - Question 2

Which of the following is a contact force:

Detailed Solution for Test: Force & Pressure - 3 - Question 2

The frictional force is a contact.
These are the forces that act upon bodies when they are in physical contact with each other and one body is trying to slide over the other body.

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Test: Force & Pressure - 3 - Question 3

Which of these is an example of a non-contact force?

Detailed Solution for Test: Force & Pressure - 3 - Question 3

Magnetic force is a force, like gravity, that is able to act across a distance without touching an object that is attracted by it. So magnetic force is a non-contact force.

Test: Force & Pressure - 3 - Question 4

How could you place an empty bottle on a table so that it produces the greatest amount of pressure on the table?

Detailed Solution for Test: Force & Pressure - 3 - Question 4

We know,
Pressure = Force/Area

The empty bottle will exert equal force (weight of the bottle) in all three positions.
Pressure ∝ 1/Area
The area of contact is minimum for position 2. Therefore, the empty bottle on the table produces the greatest amount of pressure on the table in position 2.

Test: Force & Pressure - 3 - Question 5

Tick the most appropriate answer.
If F is a force acting normally on a surface of area A, then the pressure P is given by:

Detailed Solution for Test: Force & Pressure - 3 - Question 5

We know that pressure is defined as force acting normally per unit area of a surface.
It is given by
Pressure = Forece/Area = F/A

Test: Force & Pressure - 3 - Question 6

A wooden piece 5N in weight and  5cm x 3cm x 2cm in size lies on 5cm x 2cm face. The pressure exerted by it in  N per cm2 is:

Detailed Solution for Test: Force & Pressure - 3 - Question 6

Test: Force & Pressure - 3 - Question 7

To move at the same speed, a car with a flat face and another with a streamlined body will require a different amount of force from the engine. The engine of the streamline bodied car will:

Detailed Solution for Test: Force & Pressure - 3 - Question 7

Friction opposes the relative motion between two surfaces in contact. Fluid friction can be minimized by giving suitable shapes to bodies moving in fluids. A car with a streamlined body suffers less air friction while moving and a car with a flat face will suffer higher air friction. As a result car with a streamlined body will require less force from the engine to maintain the same speed.

Test: Force & Pressure - 3 - Question 8

which of the following statement is correct

Detailed Solution for Test: Force & Pressure - 3 - Question 8
  • Statement 1 is incorrect: Pressure is defined as force per unit area, meaning it is directly proportional to the force applied and inversely proportional to the area over which it is applied.
  • Statement 2 is correct: The moment arm is indeed the perpendicular distance from the pivot point to the line of action of the force, crucial in calculating torque.
  • Statement 3 is misleading: Wooden sleepers help distribute weight, reducing pressure on the tracks, not necessarily increasing pressure.
  • Statement 4 is incorrect: Pressure can be affected by surface roughness, as it can influence the contact area and force distribution.
Test: Force & Pressure - 3 - Question 9

A vehicle sinks into soft ground. The vehicle is changed so that it does not sink as far. Which change is made?

Detailed Solution for Test: Force & Pressure - 3 - Question 9

We know that Pressure = thrust/area
The weight of vehicle with narrow tyre and the one with wide tyre is the same. That means the thrust is equal in both cases. But we can change the effect of this thrust by changing the area on which it acts. The vehicle sinks into soft ground when the pressure is more, i.e the area is less.
 To decrease the pressure, wider tyres must have been used. This increases the area on which thrust acts. So that the vehicle does't sink into the soft ground.

Test: Force & Pressure - 3 - Question 10

When we press the bulb of 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:

Detailed Solution for Test: Force & Pressure - 3 - Question 10

The rise of water in the dropper is due to atmospheric pressure.
When the bulb of a dropper is pressed, the pressure inside the dropper decreases and this causes the water to go inside the dropper.

Test: Force & Pressure - 3 - Question 11

On a body, a force of 5N is applied towards North and another force of 2N is applied towards South. Net force on the body is

Detailed Solution for Test: Force & Pressure - 3 - Question 11

When forces are applied inn the opposite directions, the forces get subtracted.
So, net force on the body = (5-2)N = 3N

Test: Force & Pressure - 3 - Question 12

At what position the fluid experiences more pressure

Detailed Solution for Test: Force & Pressure - 3 - Question 12

The pressure at a point in the fluid is due to the weight of the fluid above that point, acting on unit area.
Since the weight above the bottommost point is the highest, the pressure is maximum at that point.

Test: Force & Pressure - 3 - Question 13

In terms of physics, which of the following are considered as fluids?

Detailed Solution for Test: Force & Pressure - 3 - Question 13

A fluid is defined as a substance that has no fixed shape and yields easily to external pressure. They are free to flow, and hence the name fluid. They are of two kinds- Gases and Liquids.

Solids are not classified as fluids as they have a definite shape and volume.

Test: Force & Pressure - 3 - Question 14

Fluid pressure comprises of which of the following pressures?

Detailed Solution for Test: Force & Pressure - 3 - Question 14

A fluid is defined as a substance that has no fixed shape and yields easily to external pressure. They are of two kinds- Gases and Liquids.
The fluid pressure is, thus, of two kinds.
One is due to gases(air) and is called air pressure.
The other is due to liquids(water) and is called water pressure.

Test: Force & Pressure - 3 - Question 15

Why does a sharp knife enable us to cut through things more easily?

Detailed Solution for Test: Force & Pressure - 3 - Question 15

The pressure is defined as the force per unit area. i.e  P=F/A
So the pressure depends on the force F and area A of contact.
If force is constant, the pressure is only depends on the area. 
A sharp knife edge has small area of contact and less area of contact will produce the more pressure. 
Thus, the option B can be correct.  

Test: Force & Pressure - 3 - Question 16

Liquid pressure at a point in a liquid does not depend on the

Detailed Solution for Test: Force & Pressure - 3 - Question 16

The expression of the pressure at a point in a fluid is given by P=hρg
where. 
h; depth of the point from the surface, 
ρ; be the density of the fluid and 
g; acceleration due to gravity
Thus, the pressure in liquid at a point does not depend on the shape of the vessel in which the liquid is kept.

Test: Force & Pressure - 3 - Question 17

Compare the pressure exerted by a sharp needle on a surface and the pressure exerted by a blunt needle.

Detailed Solution for Test: Force & Pressure - 3 - Question 17

Pressure is defined as P = Force applied/Area

So the pressure applied is inversely proportional to the area to which it is applied.

Since in a sharp needle, surface area on which the force is applied, is less than that for a blunt needle.

Hence, pressure exerted by a sharp needle is more than blunt needle. 

Test: Force & Pressure - 3 - Question 18

The non-contact force is :

Detailed Solution for Test: Force & Pressure - 3 - Question 18

Force due to gravity
These are the forces that are experienced by the bodies without any physical contact with each other.

Test: Force & Pressure - 3 - Question 19

A force is needed to :

Detailed Solution for Test: Force & Pressure - 3 - Question 19

Force is an effort that comes into use to Change the state of motion or state of rest of the body. 

Test: Force & Pressure - 3 - Question 20

Consider the following two cases which involve the motion of an object and tell which option is correct.
Case 1: An apple falling from a tree towards the ground.
Case 2: To move a loaded cart on the horizontal ground.

Detailed Solution for Test: Force & Pressure - 3 - Question 20

Force is an external agent (push or pull) which changes the state of motion or rest of an object.
Case 1: An apple falling from a tree towards the ground involves the pulling of the apple by the earth's gravitational force.
Case 2: A loaded cart on the horizontal ground can be moved by both pulling or pushing force.

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