Friction (Static Kinetic Rolling) — Practice Questions

Free NEET Physics multiple-choice questions on Friction (Static Kinetic Rolling). Attempt each question and reveal the answer with a full explanation.

A block is placed on a rough inclined plane of inclination . As is increased, the block does not move until = 45 . The coefficient of static friction is: 1 0.5 0.707 0.866 The coefficient of static friction between a block and a horizontal surface is 0.5 . The angle of friction is: -1 (0.5) -1 (0.5) -1 (0.5) 30 A body of mass 2 kg is kept on a rough horizontal surface. The coefficient of static friction is 0.5 . A horizontal force of 2.5 N is applied to the body. The frictional force acting on the body is: ( g = 10 m/s 2 ) 2.5 N 10 N 5 N Zero Which of the following statements about friction is true? Kinetic friction is always less than static friction. Friction always opposes the motion of a body. Friction depends on the area of contact. Friction is a fundamental force of nature. A block of mass m is on a rough inclined plane of angle . The coefficient of static friction is s . The maximum value of for which the block does not slip is called: Angle of repose Angle of friction Critical angle Angle of contact A block of mass m is on an inclined plane of angle . If the coefficient of static friction is s , the maximum force of friction that can act on the block is: s mg s mg mg s mg A block of mass m is sliding down a rough inclined plane of inclination with constant velocity. The coefficient of kinetic friction is: The maximum static frictional force is: always greater than kinetic friction always equal to kinetic friction always less than kinetic friction sometimes less than kinetic friction A body of mass m is kept on a rough horizontal surface (coefficient of friction ). A horizontal force F is applied. The frictional force f acting on the body is: F , if F < mg mg , if F < mg zero always mg A block of mass m is stationary on a rough inclined plane of inclination . The force of friction is: mg s mg mg k mg A block of mass 1 kg is pushed against a rough vertical wall with a horizontal force of 20 N. If the coefficient of static friction is 0.6 , the frictional force acting on the block is: ( g = 10 m/s 2 ) 10 N 12 N 6 N 20 N The coefficient of kinetic friction depends on which of the following factors? Nature of the surfaces in contact The apparent area of contact The velocity of the sliding body The shape of the body A block of mass m is at rest on a rough horizontal plane. The coefficient of static friction is . A pull F is applied at an angle with the horizontal. The minimum force required to just move the block is: mg / ( + ) mg / ( - ) mg mg / A body is sliding down an inclined plane of 30 with an acceleration g/4 . The coefficient of kinetic friction is: 1 / (2 3 ) 1 / 3 3 / 2 1 / 2 A uniform chain of length L is placed on a rough horizontal table. If the coefficient of friction is , the maximum length of the chain that can hang over the edge of the table without the whole chain sliding is: L / (1 + ) L L / (1 + ) L / (1 - ) A block of mass m is pushed against a vertical wall with a horizontal force F . The coefficient of static friction is s . The minimum force F required to prevent the block from falling is: mg/ s s mg mg Zero A block of mass m is pushed up a rough inclined plane of inclination with a constant velocity. If the coefficient of friction is , the force required is: mg( + ) mg( - ) mg mg 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 them is = 0.5 . The distance that the box will move relative to belt before coming to rest on it is: ( g = 10 m/s 2 ) 0.4 m 1.2 m 0.6 m 0.2 m A block of mass m is in contact with the cart C as shown in the figure. The coefficient of static friction between the block and the cart is . The acceleration of the cart that will prevent the block from falling is: > g / < g / > g / 2 > g The coefficient of static friction s 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/s 2 ) 0.4 kg 2.0 kg 4.0 kg 0.2 kg An object is kept on a smooth conveyor belt moving with a constant velocity v . If the object is released from rest relative to the ground, what is the work done by the belt on the object until it stops slipping? 1 2 mv 2 mv 2 1 4 mv 2 Zero A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30 , the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively: 0.6 and 0.5 0.5 and 0.6 0.4 and 0.3 0.6 and 0.6 A block of mass M is being pulled by a horizontal force F on a rough surface with coefficient of friction . If the block moves with constant velocity, the power delivered by the force is: Mg v Fv M ( Mg + F)v Mgv A block of mass m is placed on a surface with vertical cross-section given by y = x 3/6 . If the coefficient of friction is 0.5 , the maximum height above the ground at which the block can be placed without slipping is: 1/6 m 2/3 m 1/3 m 1/2 m The time taken by a body to slide down a rough 45 inclined plane is n times the time taken to slide down a frictionless 45 inclined plane. The coefficient of kinetic friction between the body and the plane is: k = 1 - 1/n 2 k = 1 - 1/n k = 1 - 1/n 2 k = 1 + 1/n 2 The force required to just move a body up an inclined plane is double the force required to just prevent it from sliding down. If is the angle of friction and is the angle of inclination, then: = 3 = 2 = = 3 A block of mass M is pulled by a force F on a horizontal surface. A second block of mass m is placed on top of M . If the coefficient of friction between the two blocks is , the maximum force F that can be applied to M such that m does not slip on M is (surface below M is smooth): g(M + m) mg Mg g M / m A force F is applied on a block of mass M at an angle with the horizontal. If the block is just about to slide, and the coefficient of static friction is s , the minimum value of F is: s Mg + s s Mg + s s Mg - s s Mg - s A block of mass m is placed on a rough horizontal surface with coefficient of friction . A force F is applied on the block at an angle with the vertical. The block just starts to move. The force F is: mg - mg - mg + mg + A block of mass m is placed on a rough horizontal surface. A force P is acting on the block at an angle to the horizontal to move it with constant velocity. The value of P is minimum when: = = 1/ = = When a body is moving on a surface, the force of friction is called: Kinetic friction Static friction Limiting friction Rolling friction A block of mass m is pressed against a vertical wall with a horizontal force F . If the coefficient of static friction is s , the minimum value of F required to keep the block from falling is: mg/ s s mg mg mg/ k If the coefficient of friction between a body and a horizontal plane is = 1/ 3 , the angle of friction is: 30 45 60 90 It is easier to pull a lawn roller than to push it because: the vertical component of the pulling force reduces the effective weight and hence the friction. the vertical component of the pulling force increases the normal reaction. the horizontal component of the force is greater in pulling. the coefficient of friction is less in pulling. A block of mass m is placed on a large conveyor belt moving with a constant acceleration a . If the coefficient of static friction is s , the maximum acceleration a for which the block does not slip on the belt is: s g s / g g / s s 2 g A car of mass m is moving on a level road. If the coefficient of static friction between the tires and the road is s , the maximum stopping distance of the car moving with velocity v is: v 2 / (2 s g) v 2 / ( s g) v / (2 s g) v 2 / (2g)