MCQ Questions for Class 8 Physics Force And Pressure Quiz 1

A ball of dough is rolled into a flat chapatti. Name the force exerted to change the shape of the dough.

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Electric Force
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Compression Force
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Expansion Force
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Free Force

If you push a light object continuously, its speed:

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will keep on increasing.
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will keep on decreasing.
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will remain same.
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will become zero.

Fill in the blanks:

A force applied on an object can change its ________.

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mass
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state of motion
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temperature
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None of the above

A body is imparted motion from rest to move in a straight line. If it is obstructed by an opposite force, then:

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the body necessarily changes its direction
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the body is sure to slow down
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the body will necessarily continue to move in the same direction at the same speed
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none of these

The SI unit of force is:

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Dyne
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Gram-weight
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Newton
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None of these

Explanation

Force is an external agent (push or pull) which can change the state of motion or rest of an object. The SI unit of force is Newton

$N$ .

An object rests on a horizontal fricitionless surface. A horizontal force of magnitude F is applied. This force produces an acceleration:

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Only if F is larger than the weight of the object
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Only while the object suddenly changes from rest to motion
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Always
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Only if the inertia of the object decreases

Which of the following forces are called fundamental forces:
a) Gravitational force
b) Frictional force
c) Electrostatic force
d) Elastic force
e) Nuclear forces
f) Force due to surface tension

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b,d.f
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a,c,e
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a, b, d, f
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a, b, c, d,e, f

The magnitude of non-contact force depends upon:

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Distance between two bodies
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Mass of the two bodies
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Chemical properties of the two bodies
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All of the above

Fruits detached from a tree fall down due to force of gravity. We know that a force arises due to interaction between two objects. Name the objects interacting in this case.

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Earth and tree
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Earth and fruit
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Earth and branch
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None of the above

In which of the following events a pushing force is involved?

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Badminton
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Javelin
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Archery
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Bowling

A force cannot be seen but the effect of the force can be felt.

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True
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False

While opening a tap with two fingers, the forces applied are :

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Equal in magnitude
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Parallel to each other
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Opposite in direction
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All the above

Fill in the blank

The common water pump works on the principle that the atmosphere exerts _____.

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Torceilian
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Pressure
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Sea level
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None

Why does nose start bleeding on high mountains?

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pressure inside body > atmosphere pressure
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pressure inside body < atmosphere pressure
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pressure inside body = atmosphere pressure
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None of the above reason is correct

Which is not the unit of Force?

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Pound
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Dyne
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Joule
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Newton

Explanation

$\textbf{Hint}$ Apply newton's second law of motion.

STEP (1): SI Unit

Force acting on the body may affect the shape of the body or it will accelerate or decelerate the body, or it will give motion to the static body or it will stop the motion of the dynamic body.

$F = ma$

Where $'F'$ = force applied, $'m'$ = mass and $'a'$ = acceleration

Acceleration $a = \dfrac vt$

Where $v$ = velocity (in m/s)

Here $'m'$ is mass and $'s'$ is seconds

Time $'t'$ is in seconds

Therefore acceleration unit is = $\dfrac{\dfrac ms}s = \dfrac m{s^2}$

Hence unit of force = $kg \dfrac m{s^2} = Newton$ (in S.I. unit) i.e, option $D$ is a unit of force

Newton can converted into Pound

that is 1 Newton = 0.22481 pound ( in FPS system ) i.e, option $A$ is unit of force

$\textbf{Step2:CGS Unit}$

$F = \dfrac{g.cm}{s^2} = Dyne$ (in C.G.S. unit) i.e, option $B$ is a unit of force

Here $'g'$ is grams , $'cm'$ is centimeters and $'s'$ is seconds

Conclusion: Joule is the correct answer because it is the unit of energy.

Opening a door is an example of:

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Contact force
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Non contact force
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Spring force
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Magnetic force

There are circumstances in which two objects exert forces on one another even though they are not touching. Such forces are called (Mark the most appropriate answer)

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non-contact forces
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contact forces
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electric forces
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attractive forces

Identify the force which is used to lift an object:

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Horizontal pull
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Horizontal push
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Vertical Pull
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Vertical Push

The force used by an archer to pull a bow is:

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Muscular force
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Friction force
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Gravitational force
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Elastic spring force

In football, a goal keeper stops a ball. This is due to:

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friction between the ball and hand of goal keeper.
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decrease in speed of ball due to air resistance.
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application of force by goal keeper.
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all of the above.

Which of the following action describes pushing by a body?

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Kicking
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Lifting
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Picking
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Opening

Force exerted is :

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Effort
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Load
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Fulcrum
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None of these

State whether true or false:

The SI unit of force is newton.

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True
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False

Explanation

The SI unit of force is the newton, symbol N. The base units relevant to force are: the metre, unit of length, symbol m, the kilogram, unit of mass, symbol kg, the second, unit of time, symbol s.

$1N = 1 \dfrac {kg m}{s^2}$

So, given statement is true.

The gravitational force is a _____ force.

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non-contact force
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contact
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frictional
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destructive

Which of the following is NOT attributable to application of force?

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rowing of a boat
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bursting of a balloon while blowing
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pedaling a cycle
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catching a moving cricket ball

Which of the following is a non contact force?

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muscular
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electrostatic attraction
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elastic spring force
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friction force

A force is applied to an object in the direction of its motion. The speed of object will .......... .

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increase
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decrease
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can't say
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remain unchanged

Explanation

Acceleration

$\vec{a} = \dfrac{\vec{F}}{m}$

This implies that the object accelerates in the same direction as that of force, hence the speed of the object will increase after applying a force in the direction of its motion.

Which of the following example describes change of shape by applying force?

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Kicking a ball to move faster.
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Switching on a fan to rotate.
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Jumping from a height.
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Tearing a paper into two pieces.

State whether the given statement is true or false :

Gravity and friction are both contact forces.

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True
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False

Which of these is not a contact force?

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Friction
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Muscular force
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Magnetic force
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None of these

CBSE Questions for Class 8 Physics Force And Pressure Quiz 1 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

CBSE Questions for Class 8 Physics Force And Pressure Quiz 1 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

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