JEE Questions for Physics Laws Of Motion Quiz 15 - MCQExams.com

Assertion Aeroplanes always fly at low altitudes.
Reason According to Newton\'s third law of motion, for every action there is an equal and opposite reaction.
  • 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 Linear momentum of a body changes even when it is moving uniformly in a circle.
Reason In uniform circular motion velocity remain constant.
  • 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 Mass is a measure of inertia of the body in linear motion.
Reason Greater the mass, greater is the force required to change its state of rest or of uniform motion.
  • 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 slope of momentum versus time curve give us the acceleration.
Reason Acceleration is given by the rate of change of momentum.
  • 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 A cyclist always bends inwards while negotiating a curve.
Reason By bending, cyclist lowers his centre of 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 The work done in bringing a body down from the top to the base along a frictionless incline plane is the same as the work done in bringing in down the vertical side.
Reason The gravitational force on the body along the inclined plane is the same as that along the vertical side.
  • 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 Linear momentum of a body changes even when it is moving uniformly in a circle.
Reason Force required to move a body uniformly along a straight line is zero.
  • 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 A bullet is fired from a rifle. If the riffle recoils freely, the kinetic energy of rifle is more than that of the bullet.
Reason In the case of rifle bullet system the law of conservation of momentum violates.
  • 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 A reference frame attached to earth is an inertial frame of reference.
Reason The reference frame which has zero acceleration is called a non inertial frame of reference.
  • 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 apparent weight of a body in an elevator moving with some downward acceleration is less then the actual weight of body.
Reason The part of the weight is spent in producing downward acceleration, when body is in elevator.
  • 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 the lift moves with uniform velocity the man in the lift will feel weightlessness.
Reason In downward accelerated motion of lift, apparent weight of a body decreases.
  • 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 Newton\'s third law of motion is applicable only when bodies are in motion.
Reason Newton\'s third law applies to all types of forces, e. g. , gravitational, electric or magnetic forces etc.
  • 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 car is moving with uniform velocity on a rough horizontal road. Therefore, according to Newton\'s first law of motion
  • No force is being applied by its engine
  • A force is surely being applied by its engine
  • An acceleration is being produced in the car
  • The kinetic energy of the car is increasing
A 60 kg man stands on a spring scale in the lift. At some instant he finds, scale reading has changed from 60 kg to 50 kg for a while and then comes back to the original mark. What should we conclude
  • The lift was in constant motion upwards
  • The lift was in constant motion downwards
  • The lift while in constant motion upwards, is stopped suddenly
  • The lift while in constant motion downwards, is suddenly stopped
Three weight A, B and C are connected by string as shown in the figure. The system moves over a frictionless pulley. The tension in the string connecting A and B is (where g is acceleration due to gravity)
Physics-Laws of Motion-77690.png
  • g
  • g/9
  • 8g/9
  • 10g/9
The masses of 10 kg and 20 kg respectively are connected by a massless spring as shown in figure. A force of 200 N acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration 12 m/sec2.What is the acceleration of 20 kg mass
Physics-Laws of Motion-77691.png
  • 12 m/sec2
  • 4 m/sec2
  • 10 m/sec2
  • Zero
As shown in the figure, two equal masses each of 2 kg are suspended from a spring balance. The reading of the spring balance will be
Physics-Laws of Motion-77692.png
  • Zero
  • 2 kg
  • 4 kg
  • Between zero and 2 kg
A player kicks a football of mass 0.5 kg and the football begins to move with a velocity of 10 m/s. If the contact between the leg and the football lasts for 1/50sec, thenthe force acted on the football should be
  • 2500 N
  • 1250 N
  • 250 N
  • 625 N
The engine of a jet aircraft applies a thrust force of 105 N during take off and causes the plane to attain avelocity of 1 km/sec in 10 sec. The mass of the plane is
  • 102 kg
  • 103 kg
  • 104 kg
  • 105 kg
Two weights w1 are w2 suspended from the ends of alight string passing over a smooth fixed pulley. If the pulley is pulled up at an acceleration g, the tension in the string will be

  • Physics-Laws of Motion-77693.png
  • 2)
    Physics-Laws of Motion-77694.png

  • Physics-Laws of Motion-77695.png

  • Physics-Laws of Motion-77696.png
Two masses M and m are connected by a weightless string. They are pulled by a force F on a frictionless horizontal surface. The tension in the string will be
Physics-Laws of Motion-77697.png

  • Physics-Laws of Motion-77698.png
  • 2)
    Physics-Laws of Motion-77699.png

  • Physics-Laws of Motion-77700.png

  • Physics-Laws of Motion-77701.png
In the above question, the acceleration mass m is

  • Physics-Laws of Motion-77702.png
  • 2)
    Physics-Laws of Motion-77703.png

  • Physics-Laws of Motion-77704.png

  • Physics-Laws of Motion-77705.png
Which one of the following is not a contact force
  • Viscous force
  • Air resistance
  • Friction
  • Buoyant force
  • Magnetic force
In relativity which is constant between two frames of reference
  • Acceleration
  • Conservation of mass
  • Space interval
  • Velocity
A block is lying static on the floor. The maximum value of static frictional force on the block is 10 N. If a horizontal force of 8 N is applied to the block, what willbe the frictional force on the blocks
  • 2 N
  • 18 N
  • 8 N
  • 10 N
A force of 98 N is required to just start moving is body of mass 100 kg over ice. The coefficient of static friction is
  • 0.6
  • 0.4
  • 0.2
  • 0.1
A block weighing W is held against a vertical wall by applying a horizontal force F. The minimum value of F needed to hold the block is
  • Less than W
  • Equal to W
  • Greater than W
  • Data is insufficient
Two balls of masses m1 and m2 are separated from each other by a powder change placed between them. The whole system is at rest on the ground. suddenly the powder charge explodes and masses are pushed apart. The mass m1 travels a distance s1 and stops. If the coefficients of friction between the balls and ground are same, the mass m2 stops after travelling the distance

  • Physics-Laws of Motion-77709.png
  • 2)
    Physics-Laws of Motion-77710.png

  • Physics-Laws of Motion-77711.png

  • Physics-Laws of Motion-77712.png
In the figure shown, a block of weight 10 N is resting on a horizontal surface. The coefficient of static friction between the block and the surface µs = 0.4. A force of 3.5 N will keep the block in uniform motion, once it has been set in motion. A horizontal force of 3 N is applied to the block, then the block will
Physics-Laws of Motion-77714.png
  • Move over the surface with constant velocity
  • Move having accelerated motion over the surface
  • Not move
  • First it will move with a constant velocity for some time and then will have accelerated motion
A lift is moving downwards with an acceleration equal to acceleration due to gravity. A body of mass m kept on the floor of the lift is pulled horizontally. If the coefficient of friction is µ, then the frictional resistance offered by the body is
  • mg
  • µmg
  • 2µmg
  • Zero
A uniform rope of length l lies on a table. If the coefficient of friction is µ, then the maximum length l of the part of this rope which can overhang from the edge of the table without sliding down is

  • Physics-Laws of Motion-77716.png
  • 2)
    Physics-Laws of Motion-77717.png

  • Physics-Laws of Motion-77718.png

  • Physics-Laws of Motion-77719.png
Which of the following statements is not true
  • The coefficient of friction between two surfaces increases as the surface in contact are made rough
  • The force of friction acts in a direction opposite to the applied force
  • Rolling friction is greater than sliding friction
  • The coefficient of friction between wood and wood is less than 1
A block of 1 kg is stopped against a wall by applying a force F perpendicular to the wall. If µ = 0.2, then minimum value of F will be
  • 980 N
  • 49 N
  • 98 N
  • 490 N
The coefficient of static friction, µs, between block A of mass 2 kg and the table as shown in the figure is 0.2. What would be the maximum mass value of block B, so that the two blocks do not move ? The string and the pulley are assumed to be smooth and massless.(g = 10 m/s2)
Physics-Laws of Motion-77723.png
  • 2.0 kg
  • 4.0 kg
  • 0.2 kg
  • 0.4 kg
When two surfaces are coated with a lubricant, then they
  • Stick to each other
  • Side upon each other
  • Roll upon each other
  • None of these
A 20 kg block is initially at rest on a rough horizontal surface. A horizontal force of 75 N is required to set the block in motion. After it is in motion, a horizontal force of 60 N is required to keep the block moving with constant speed. The coefficient of static friction is
  • 0.38
  • 0.44
  • 0.52
  • 0.60
A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizontal rope tied to a wall holds it. The coefficient of friction between A and B is 0.2, while coefficient of friction between B and the ground is 0.3. The minimum required force F to start moving B will be
Physics-Laws of Motion-77726.png
  • 900 N
  • 100 N
  • 1100 N
  • 1200 N
A box is lying on a inclined plane what is the coefficient of static friction, if the box starts sliding when an angle of inclination is 60°
  • 1.173
  • 1.732
  • 2.732
  • 1.677
A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4. If a force F of 2.5 Newton\'s is applied on the block as shown in the figure, the frictional force between the block and the floor will be
Physics-Laws of Motion-77729.png
  • 10 N
  • 2.5 N
  • 5 N
  • 7.84 N
If a ladder weighing 250 N is placed against a smooth vertical wall having coefficient of friction between it and floor is 0.3, then what is the maximum force of friction available at the point of contact between the ladder and the
  • 75 N
  • 50 N
  • 35 N
  • 25 N
Which activity is not based upon friction
  • Writing
  • Speaking
  • Hearing
  • Walking
A body of mass 2 kg is being dragged with uniform velocity of 2 m/s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is= 4.2 j/cal and g = 9.8 m/s2)
  • 9.33 cal
  • 10.21 cal
  • 12.67 cal
  • 13.34 cal
Two carts of masses 200 kg and 300 kg on horizontal rails are pushed apart. Suppose the coefficient of friction between the carts and the rails are same. If the 200 kg cart travels a distance of 36 m and stops, then the distance travelled by the cart weighing 300 kg is
Physics-Laws of Motion-77738.png
  • 32 m
  • 24 m
  • 16 m
  • 12 m
A body B lies on a smooth horizontal table and another body A is placed on B. The coefficient of friction between A and B is g. What acceleration give to B will cause slipping to occur between A and B
  • µg
  • g/µ
  • µ/g

  • Physics-Laws of Motion-77740.png
Direction of frictional force between wheel of the carand road is
Physics-Laws of Motion-77742.png
  • Upward
  • Forward
  • Backward
  • Downward
A body of 10 kg is acted by a force of 129.4 N. If g = 9.8 m/sec2. The acceleration of the block is 10 m/s2.What is the coefficient of kinetic friction
  • 0.03
  • 0.01
  • 0.30
  • 0.25
Consider a car moving along a straight horizontal road with a speed of 72 km/h. If the coefficient of kinetic friction between the tyres and the road is 0.5, the shortest distance in which the car can be stopped is [g =10 m/s2) is
  • 30 m
  • 40 m
  • 72 m
  • 20 m
A 500 kg horse pulls a cart of mass 1500 kg along a level road with an acceleration of 1 m/s2. If the coefficient ofsliding friction is 0.2, then the force exerted by the horse in forward direction is
  • 3000 N
  • 4000 N
  • 5000 N
  • 6000 N
The maximum speed of a car on a road turn of radius30 m, if the coefficient of friction between the tyres andthe road is 0.4; will be
  • 9.84 m/s
  • 10.84 m/s
  • 7.84 m/s
  • 5.84 m/s
A block of mass 50 kg slides over a horizontal distance of 1 m. If the coefficient of friction between their surfaces is 0.2, then work done against friction is
  • 98 J
  • 72 J
  • 56 J
  • 34 J
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