JEE Questions for Physics Laws Of Motion Quiz 16 - MCQExams.com

On the horizontal surface of a truck (µ = 0.6), a block of mass 1 kg is placed. If the truck is accelerating at the rate of 5 m/sec2, then frictional force on the block will be
  • 5 N
  • 6 N
  • 5.88 N
  • 8 N
A vehicle of mass m is moving on a rough horizontal road with momentum P. If the coefficient of friction between the tyres and the road be µ, then the stopping distance is

  • Physics-Laws of Motion-77750.png
  • 2)
    Physics-Laws of Motion-77751.png

  • Physics-Laws of Motion-77752.png

  • Physics-Laws of Motion-77753.png
A body of weight 64 N is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be (Acceleration due to gravity = g)

  • Physics-Laws of Motion-77755.png
  • 0.64 g

  • Physics-Laws of Motion-77756.png
  • 0.2 g
A block of mass 10 kg is placed on a rough horizontal surface having coefficient of friction µ = 0.5. If a horizontal force of 100 N is acting on it, then acceleration of the block will be
  • 0.5 m/s2
  • 5 m/s2
  • 10 m/s2
  • 15 m/s2
Two iron blocks of equal mass but with double surface area slide down an inclined plane with friction coefficient µ. If the first block with surface area. A experience a frictional force f, then the second block with surface area 2A will experience a frictional force
  • f/2
  • f
  • 2f
  • 4f
A body of mass 5 kg rests on a rough horizontal surface of coefficient of friction 0.2. The body is pulled through a distance of 10 m by horizontal force of 25 N. The kinetic energy acquired by it is (g = 10 m/s2)
  • 330 J
  • 150 J
  • 100 J
  • 50 J
A motorcycle is travelling on a curved track of radius 500m. If the coefficient of friction between road and tyres is 0.5, the speed avoiding skidding will be
  • 50 m/s
  • 75 m/s
  • 25 m/s
  • 35 m/s
A fireman of mass 60 kg slides down a pole. He is pressing the pole with a force of 600 N. The coefficient of friction between the hands and the pole is 0.5, with what acceleration will the fireman slide down(g = 10 m/s2)
  • 1 m/s2
  • 2.5 m/s2
  • 10 m/s2
  • 5 m/s2
A block of mass M = 5 kg is resting on a rough horizontal surface for which the coefficient of friction is 0.2. When a force F = 40 N is applied, the acceleration of the block will be (g = 10 m/s2)
Physics-Laws of Motion-77763.png
  • 5.73 m/sec2
  • 8.0 m/sec2
  • 3.17 m/sec2
  • 10.0 m/sec2
Consider a car moving on a straight road with a speed of 100 m/s. The distance at which car can be stopped is [µk = 0.5]
  • 100 m
  • 400 m
  • 800 m
  • 1000 m
A block B is pushed momentarily along a horizontal surface with an initial velocity V. if µ is the coefficient of sliding friction between B and the surface, block B willcome to rest after a time
Physics-Laws of Motion-77766.png
  • V / (gµ)
  • gµ /V
  • g/V
  • V/g
A gramophone record is revolving with an angular velocity ω. A coin in placed at a distance r from the centre of the record. The static coefficient of friction is µ. The coin will revolve with the record if

  • Physics-Laws of Motion-77768.png
  • 2)
    Physics-Laws of Motion-77769.png

  • Physics-Laws of Motion-77770.png

  • Physics-Laws of Motion-77771.png
An iron block of mass 5 kg is kept on a trolley. If the trolley is being pushed with an acceleration of 5 m/s2. What will be the force of friction between the block and the trolley Surface? (Take the coefficient of static friction between the block and the surface to be 0.8).
  • Zero
  • 5 N
  • 4 N
  • 25 N
A conveyor belt is moving at a constant speed of 2 m/s. A box is gently dropped on it. The coefficient of friction between then is µ = 0.5. The distance that the box will move relative to belt before coming to rest on it, taking g = 10 ms–2 is
  • Zero
  • 0.4 m
  • 1.2 m
  • 0.6 m
A block of base 10 cm × 10 cm and height 15 cm is kept on an inclined plane. The coefficient of friction between them √3. The inclination θ of this inclined plane from the horizontal plane is gradually increased from 0°. Then
  • At θ = 30°, the block will start sliding down the plane
  • The block will remain at rest on the plane up to certain θ and then it will topple
  • At θ = 60°, the block will start sliding down the plane and continue to do so at higher angles
  • At θ = 60°, the block will start sliding down the plane and on further increasing 0, it will topple at certain 0
A block is at rest on an inclined plane making an angle αwith the horizontal. As the angle α of the incline is increased, the block starts slipping when the angle of inclination becomes θ. The coefficient of static friction between the block and the surface of the inclined plane is or a body starts sliding down at an angle θ to horizontal. Then coefficient of friction is equal to
  • sin θ
  • cos θ
  • tan θ
  • Independent of θ
A given object takes n times as much time to slide down a 45° rough incline as it takes to slide down a perfectly smooth 45° incline. The coefficient of kinetic friction between the object and the incline is given by

  • Physics-Laws of Motion-77777.png
  • 2)
    Physics-Laws of Motion-77778.png

  • Physics-Laws of Motion-77779.png

  • Physics-Laws of Motion-77780.png
Starting from rest, a body slides down a 45° inclined plane in twice the time it takes to slide down the same distance in the absence of friction. The coefficient of friction between the body and the inclined plane is
  • 0.33
  • 0.25
  • 0.75
  • 0.80
The coefficient of friction between a body and the surface of an inclined plane at 45° is 0.5. Ifg = 9.8 m/s2, the acceleration of the body downwards in m/s2

  • Physics-Laws of Motion-77784.png
  • 2)
    Physics-Laws of Motion-77785.png

  • Physics-Laws of Motion-77786.png
  • 4.9
A block is kept on an inclined plane of inclination θ of length l The velocity of particle at the bottom of inclined plane is (the coefficient of friction is µ)

  • Physics-Laws of Motion-77788.png
  • 2)
    Physics-Laws of Motion-77789.png

  • Physics-Laws of Motion-77790.png

  • Physics-Laws of Motion-77791.png
A brick of mass 2 kg begins to slide down on a plane inclined at an angle of 45° with the horizontal. Theforce of friction will be
  • 19.6 sin 45°
  • 19.6 cos 45°
  • 9.8 sin 45°
  • 9.8 cos 45°
The upper half of an inclined plane of inclination θ is perfectly smooth while the lower half is rough. A body starting from the rest at top comes back to rest at the bottom, if the coefficient of friction for the lower half is given by
  • µ = sin θ
  • µ = cos θ
  • µ= 2 cos θ
  • µ= 2 tan θ
A block of mass 1 kg slides down on a rough inclined plane of inclination 60° starting from its top. If the coefficient of kinetic friction is 0.5 and length of the plane is 1 m, then work done against friction is (Take g = 9.8 m/s2)
  • 9.82 J
  • 4.94 J
  • 2.45 J
  • 1.96 J
A body of 5 kg weight kept on a rough inclined plane of angle 30° starts sliding with a constant velocity. Then the coefficient of friction is (assume g = 10 m/s2)

  • Physics-Laws of Motion-77796.png
  • 2)
    Physics-Laws of Motion-77797.png

  • Physics-Laws of Motion-77798.png

  • Physics-Laws of Motion-77799.png
300 Joule of work is done is sliding up a 2 kg block on an inclined plane to a height of 10 metres. Taking value of acceleration due to gravity `g\' to be 10 m/s2, workdone against friction is
  • 100 J
  • 200 J
  • 300 J
  • Zero
A block on mass m lying on a rough horizontal plane is acted upon by a horizontal force P and another force Q inclined at an angle θ to the vertical. The block will remain in equilibrium, if the coefficient of friction between it and the surface is
Physics-Laws of Motion-77802.png

  • Physics-Laws of Motion-77803.png
  • 2)
    Physics-Laws of Motion-77804.png

  • Physics-Laws of Motion-77805.png

  • Physics-Laws of Motion-77806.png
Which of the following is correct, when a person walks on a rough surface
  • The frictional force exerted by the surface keeps him moving
  • The force which the man exerts on the floor keeps him moving
  • The reaction of the force which the man exerts on floor keeps him moving
  • None of the above
A body of mass M is kept on a rough horizontal surface (friction coefficient µ). A person a trying to pull the body by applying a horizontal force but the body is not moving. The force by the surface on the body is F, where

  • Physics-Laws of Motion-77809.png
  • 2)
    Physics-Laws of Motion-77810.png

  • Physics-Laws of Motion-77811.png

  • Physics-Laws of Motion-77812.png
A 40 kg slab rests on a frictionless floor as shown in the figure. A 10 kg block rests on the top of the slab. The static coefficient of friction between the block and slab is 0.60 while the kinetic friction is 0.40. The 10 kg block is acted upon by a horizontal force 100 N. If g = 9.8 m/s2, the resulting acceleration of the slab will be
Physics-Laws of Motion-77814.png
  • 0.98 m/s2
  • 1.47 m/s2
  • 1.52 m/s2
  • 6.1 m/s2
Assertion On a rainy day, it is difficult to drive a car or bus at high speed.
Reason The value of coefficient of friction is lowered due to wetting of the surface.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion when a bicycle is in motion, the force of friction exerted by the ground on the two wheels is always in forward direction.
Reason The frictional force acts only when the bodies are in contact.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The velocity of a body at the bottom of an inclined plans of given height is more when it slides down the plane, compared to, when it rolling down the same plane.
Reason In rolling down a body acquires both, kinetic energy of translation and rotation
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Angle of repose is equal to angle of limiting friction.
Reason When the body is just at the point of motion, the force of friction in this state is called as limiting friction.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Two bodies of masses M and m(M > m) are allowed to fall from the same height, if the air resistance for each be the same, then both the bodies will reach the earth simultaneously.
Reason For same air resistance, acceleration of both the bodies will be same.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Friction is a self adjusting force.
Reason Friction does not depend upon mass of the body.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The value of dynamic friction is less than the limiting friction.
Reason Once the motion has started, the inertia of rest has been overcome.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The acceleration of a body down a rough inclined plane is greater than the acceleration due to gravity.
Reason The body is able to slide on a inclined plane only when its acceleration is greater than acceleration due to gravity.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Use of ball bearings between two moving parts of machine is a common practice.
Reason Ball bearings reduce vibrations and provide good stability.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
A force of 19.6 N when applied parallel to the surface just moves a body of mass 10 kg kept on a horizontal surface. If a 5 kg mass is kept on the first mass, the force applied parallel to the surface to just move the combined body is
  • 29.4 N
  • 39.2 N
  • 18.6 N
  • 42.6 N
If the normal force is doubled, the coefficient of friction is
  • Not changed
  • Halved
  • Doubled
  • Tripled
A body of weight 50 N placed on a horizontal surface is just moved by a force of 28.2 N. The frictional force and the normal reaction are
Physics-Laws of Motion-77815.png
  • 10 N, 15 N
  • 20 N, 30 N
  • 2 N, 3 N
  • 5 N, 6 N
A motor car has a width 1.1 m between wheels. Its centre of gravity is 0.62 m above the ground and the coefficient of friction between the wheels and the road is 0.8. What is the maximum possible speed, if the centre of gravity inscribes a circle of radius 15 m? (Road surface is horizontal )
  • 7.64 m/s
  • 6.28 m/s
  • 10.84 m/s
  • 11.23 m/s
A rough vertical board has an acceleration \'a\' so that a 2 kg block pressing against it does not fall. The coefficient of friction between the block and the board should be
Physics-Laws of Motion-77816.png
  • >g/a

  • = g/a
  • >a/g
A stone weighing 1 kg and sliding on ice with a velocity of 2 m/s is stopped by friction in 10 sec. The force of friction (assuming it to be constant) will be
  • –20 N
  • –0.2 N
  • 0.2 N
  • 20 N
0:0:1


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