CBSE Questions for Class 9 Physics Force And Laws Of Motion Quiz 8 - MCQExams.com

Vehicles are provided with shock absorbers. Which of the following laws of Newton given below explain this?
  • The first law of motion
  • The second law of motion
  • The third law of motion
  • All of the above
Which of the following statements is NOT true?
  • When the mass of a body is doubled, the momentum of a body is halved, provided the velocity remains the same.
  • The pain we feel in the hand on hitting the wall is a consequence of Newton's third law of motion.
  • A table-cloth which is pulled from a table without dislodging the dishes is due to inertia of rest.
  • Momentum is a vector quantity.
Two bodies of masses 1m and 4m have the same KE. What is the ratio of their momenta?
  • 2:1
  • 1:2
  • 1:4
  • 4:1
A 10 N force applied on a body produces in it an acceleration of $$2 \,m\, s^{-2}$$, then the mass of the body is ______.
  • 10 kg
  • 2 kg
  • 5 kg
  • 6 kg
Which of the following safety features are used in vehicles to reduce the negative effects of inertia?
(i)Safety seat belts
(ii)Automatic air bags
(iii)Absorber bumpers
  • Only (i) and (ii)
  • Only (ii) and (iii)
  • Only (i) and (iii)
  • (i), (ii) and (iii)
A man weighing 60 kg is walking with a uniform velocity of 4 m $$s^{-1}$$. Calculate the momentum of a man.
  • 120 m $$s^{-1}$$
  • 240 m $$s^{-1}$$
  • 360 m $$s^{-1}$$
  • 480 m $$s^{-1}$$
Identify the type of force in diagram
566720.jpg
  • Push
  • Pull
  • No force is acting
  • Both A and B
A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is
  • constant and equal to mg in magnitude
  • constant and greater than mg in magnitude.
  • variable but always greater than mg
  • at first greater than $$mg$$, and later becomes equal to $$mg$$.
On a stationary sail boat, air is blown from a fan attached to the boat. The boat
  • moves in opposite direction in which the air is blown
  • does not move
  • moves in the same direction in which air blows
  • spins around
Select the correct option\options:
  • When a body exerts a force on any other body, the second body also exerts an equal and opposite force on the first.
  • Forces in nature always occurs in pairs. A single isolated force is not possible
  • Any agent, applying a force also experiences a force of equal magnitude but in opposite direction. The force applied by the agent is called Action and the counter force experienced by it is called Reaction.
  • None of these
If set of forces acting on a body are balanced, the body
  • must be moving
  • must be at rest
  • must not be revolving
  • must not be accelerating
When a bus suddenly takes a turn, the passengers are thrown outwards because of 
  • Inertia of motion
  • Acceleration of motion
  • Speed of motion
  • Both (b) and (c)
A car accelerates on a horizontal road due to the force exerted by
  • The engine of the car
  • The driver of the car
  • The car on earth
  • The road on the car
What causes a moving body to resist a change in its state of motion?
  • Its acceleration
  • Its speed
  • Its inertia
  • Its weight
The net force acting is not zero on
  • a retarding train
  • a ball falling with terminal velocity
  • a kite held stationary
  • a truck moving with constant velocity
  • a book placed on a table
Inertia is that property of a body by virtue of which the body is
  • Unable to change by itself the state of uniform motion
  • Unable to change by itself the state of rest and or uniform linear motion
  • Unable to change by itself the state of rest
  • Unable to change by itself the direction if motion
The propulsion of rocket illustrates that :
  • Linear momentum is conserved
  • Newton's third law is not applicable
  • Newton's third law is applicable
  • Linear momentum is not conserved
A bowling ball hits a pin as shown, where $$F_{BP}$$ represents the force applied by the ball on the pin. Which arrow shows $$F_{PB}$$ (force applied by the pin on the ball) correctly?  
1006046_472ec64304884af4b84ea87eae0eb30e.png
Fill in the blank: 
Tendency of an object to _____ a change in its state of rest or motion is called inertia
  • Allow
  • Assist
  • Resist
  • None of these
A bullet is fired from a rifle with a velocity of $$1000\,m/s$$. Its momentum is $$20\ kg\ m/s$$. What will be its mass?
  • $$10\ g$$
  • $$20\ g$$
  • $$50\ g$$
  • $$100\ g$$

Why does an athlete take a run before doing a long jump?
  • To cheer the crowd
  • She/he likes running
  • To gain momentum
  • To reduce momentum
$$4$$ balls are moving in the directions shown. The magnitudes of their momentum are also given in the figure. Find which two have the same momentum.
1005901_0ec8ff5c1b5448298b8ebf8cf2e1f3ce.png
  • $$A$$ and  $$B$$
  • $$C$$ and $$D$$
  • $$A$$ and $$C$$
  • $$A$$ and $$D$$

The symbol and formula for momentum is
  • $$m, pv$$
  • $$p, ma$$
  • $$p, mv$$
  • $$M, mv$$
There are $$3$$ balls of same shape and size made of wood, iron and plastic. Which one of them would have highest inertia?
  • Wood
  • Iron
  • Plastic
  • None of these

The $$SI$$ units of Force are _____ or _____.
  • $$kg \ m/s,\ N$$
  • $$kg\ m/s^2, \ Ne$$
  • $$kg\ km/hr$$, Newton
  • $$kg\ m/s^2, \ N$$
Choose the correct option.
  • Balanced forces do not have any impact on a body
  • Balanced force can change shape of an object
  • Unbalanced force do not produce motion
  • None
If given is the direction of acceleration, where should the direction of force be?
1005907_9414c7bdde33440a951d4b5bf3cf4129.png
  • None of these
Which one of these is a real life application of the third law of motion?
  • Working of pulleys
  • Use of airbags in cars for safety
  • Helicopters creating lift by pushing air down
  • Cricketers pulling their hands down while taking a catch
The acceleration of a body depends on:
  • The external force acting on the body only
  • The mass of the body only
  • Both the external force and the mass
  • The displacement of the body only
 A nail driven into a wall by striking it with hammer is an example for 
  • Force
  • Impulse
  • acceleration
  • mass
0:0:1


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