CBSE Questions for Class 8 Physics Force And Pressure Quiz 7 - MCQExams.com

If a body is moving with a constant speed along a straight line; then in order to change its direction of motion, an external force has to be applied in a direction normal to the direction of motion.
  • True
  • False
Pressure varies inversely with area (A) provided the thrust is same.
  • True
  • False
Pressure varies with force (F) as (provided area is same)
  • PF
  • P1F
  • PF2
  • P1F2
A force produces translational motion:
  • When the body is free to move and applied force pass through the rotation axis
  • When the body is hindered to move
  • When the body is rigidly fixed
  • When the body is free to move and applied force does not pass through the rotation axis
 Which of the following force doesn't change with distance?
  • Electrostatic force
  • Gravitational force
  • Frictional force
  • Magnetic force
It is better to use a sharp tipped nail than a blunt nail because :
  • The tip with the smallest area will produce a higher pressure when a force is applied.
  • A sharp tipped nail needs a larger force to drive it into the wooden surface
  • The sharp tip saves cost as less raw materials are required to make such nails
  • The sharp tip has a spiralling effect when the nail is hit on the head
With the increase in the area of contact of an object, the pressure:
(Note : Thrust remains same)
  • Increases
  • Decreases
  • Is not affected
  • None of these
Which of the statements about force are true?
  • It can be seen
  • It causes an object to move
  • It is pull or a push
  • It can change the motion of an object
The pressure exerted by a women wearing shoes with pointed heels is ...... than what an elephant with one foot can exert on ground :
  • Much lesser
  • Much greater
  • Both equal
  • None of these
Fill in the blank.
Dams are ____ at the base.
  • thicker
  • thinner
  • same
  • can't say
Which of the following has infinite range?
  • Gravitational force
  • Electromagnetic force
  • Strong nuclear force
  • Both a and b
The same force acting on a smaller area exerts a larger pressure, and a smaller pressure on a larger area.
  • True
  • False
  • Ambiguous
  • Data insufficient
A box exerts a force of 420N on a floor. The bottom of the box has an area of 0.7m2. What is the pressure exerted by the box on the floor?
  • 600Pa
  • 500Pa
  • 400Pa
  • 700Pa
Ask a friend to drive a small nail into a piece of wood placed on top of a pile of books on your head. Why doesn't this hurt you?
  • Because the nail has a sharp point and thus, exert less pressure on wood
  • The force is exerted on the wood, thus it has no effect on out head
  • The relatively large mass of the books and block on your head resists being moved
  • Action-reaction forces cancel out each other
A force F1 accelerates a particle from rest to a velocity v. Another F2 decelerates the same particle from v to rest, then:
  • F1 is always equal to F2
  • F2 is greater than F1
  • F2 may be smaller than, greater than or equal to F1
  • F2 cannot be equal to F1
Porters (coolies) place a round piece of cloth on their heads, to ______ the area of contact of the load with their head.
  • increase
  • decrease
  • maintain the same
  • Cannot say
It is easier to cut with a sharp knife than with a blunt one, This is because
  • sharp knife exerts more pressure
  • sharp knife exerts less pressure
  • both knives exert equal pressure
  • sharp knife has a better grip
Buildings have wide foundations so that they exert less force on the ground or Earth.
  • True
  • False
A 1.5m wide by 2.5m long water bed weighs 1025N. Find the pressure that the water bed exerts on the floor. Assume that the entire lower surface of the bed makes contact with the floor.
  • 273.3Pa
  • 373.5Pa
  • 173.3Pa
  • 473.3Pa
Which of the following is NOT true?
  • A sharp knife can easily cut due to its small cutting surface.
  • It is easier to walk in sand than on road.
  • A battle tank can move easily on soft ground because its tracks have bigger surfaces.
  • The pressure exerted by a needle is much more than the foot of an elephant.
State whether the given statement is TRUE or FALSE.
The foundations of high-rise buildings are kept wide so that they may exert more pressure on the ground.
  • True
  • False
Force can only increase or decrease the speed of a moving object or change its direction.
  • True
  • False
State whether the given statement is TRUE or FALSE.
A liquid in a container exerts pressure in all directions-  on the bottom of the container, on its walls, and even upwards.
  • True
  • False
Tick the correct statements.
  • air exerts pressure because it occupies space and has weight.
  •  air is more dense near the earth. It goes on thinning out as we go up.
  •  oxygen content of the air goes on decreasing as we go up.
  •  air is uniformly dense right fron the earth to the sky.
  •  air pressure is very high near the earth and it goes on decreasing as we go up.
  •  99% of air exists up to a height of nearly 30km.
A mountain climber experiences a nose bleed due to:
  • Decrease in atmospheric pressure
  • Increase in atmospheric pressure
  • More gravitational pull
  • Effect of high altitude
If we apply the brakes to a moving car, it comes to rest. This shows that force can make a moving object go slower.
  • True
  • False
  • Ambiguous
  • Data insufficient
A contact force cannot act through
  • Empty space
  • Touching
  • Touching with a metal rod
  • Touching with a wooden rod
(a) A force of 200N acts on an area of 0.02m2. Find the pressure in Pascal.
(b) What force will exert a pressure of 50,000 Pa on an area of 0.5m2?
(c) Find out the area of a body which experiences a pressure of 500 Pa by a force of 100N.

  • (a)10000Pa, (b)25000N, (c)0.2m2
  • (a)1000Pa, (b)2500N, (c)2m2
  • (a)100000Pa, (b)250000N, (c)0.2m2
  • (a)100Pa, (b)250N, (c)0.2m2
Which of the following class of force is different from others?
  • Magnetic force
  • Electrical force
  • Gravitational force
  • Stretching of a spring
a. To stretch the bow, the archer applies a force that causes a change in its ______
b. The force applied by the archer to stretch the bow is an example of ______ force.
c. The type of force responsible for a change in the state of motion of the arrow is an example of a _____ force.
d. While the arrow moves towards its target, the forces acting on it are due to ______ and that due to _______ of air.
  • Shape
  • Muscular
  • Contact
  • Gravity, Friction
0:0:2


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 8 Physics Quiz Questions and Answers