Friction PYQs Set 1 (PDF)

Set 1 of 7 · Questions 1-30 of 182

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Mere Teacher · Previous Year Questions JEE Main Physics · Friction · Set 1 (Q1-30)
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1. $A particle is placed at rest inside a hollow hemisphere of radius R . The coefficient of friction between the particle and the hemisphere is μ = \frac{1}{3} . The maximum height upto which the particle can remain stationary is$ (1) $\frac{R}{2}$ (2) $(1 - \frac{3}{2}) R$ (3) $\frac{3}{2} R$ (4) $\frac{3 R}{8}$ 2. $A block of mass 5 kg is moving on an inclined plane which makes an angle of 30^{\circ} with the horizontal. Friction coefficient between the block and inclined plane surface is \frac{3}{2} . The force to be applied on the block so that the block will move down without acceleration is____N. (g = 10 m / s^{2}) .$ (1) $25$ (2) $7.5$ (3) $12.5$ (4) $15$ 3. $A body of mass 1 kg is moving with a velocity 10 ms^{- 1} due to a constant force on a horizontal rough surface having coefficient of kinetic friction 0.4. If the constant force is removed, the body comes to rest in a time (Acceleration due to gravity = 10 ms^{- 2})$ (1) $2.5 s$ (2) $4 s$ (3) $0.4 s$ (4) $0.25 s$ 4. $A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is [NEET 2023]$ (1) $along northward$ (2) $along north-east$ (3) $along south-west$ (4) $along eastward$ 5. $A smooth block is released from rest on a 45º incline and then slides a distance d. The time taken to slide is n times as much to slide on rough incline than on a smooth incline. The coefficient of friction is-$ (1) $μ_{s} = 1 - \frac{1}{n ^{2}}$ (2) $μ_{s} = 1 - \frac{1}{n ^{2}}$ (3) $μ_{k} = 1 - \frac{1}{n ^{2}}$ (4) $μ_{k} = 1 - \frac{1}{n ^{2}}$ 6. $A block of mass 1 kg, moving along x with speed v_{i} = 10 m / s enters a rough region ranging from x = 0.1 m to x = 1.9 m . The retarding force acting on the block in this range is F_{r} = - krN, with k = 10 N / m . Then the final speed of the block as it crosses rough region is.$ (1) $4 m / s$ (2) $10 m / s$ (3) $8 m / s$ (4) $6 m / s$ 7. $A small block of mass 100 g is tied to a spring of spring constant 7. 5 N m^{- 1} and length 20 cm. The other end of spring is fixed at a particular point A. If the block moves in a circular path on a smooth horizontal surface with constant angular velocity 5 rad s^{- 1} about point A, then tension in the spring is$ (1) $0.75N$ (2) $0.25N$ (3) $0.50 N$ (4) $1.5N$ 8. $A light unstretchable string passing over a smooth light pulley connects two blocks of masses m_{1} and m_{2} . If the acceleration of the system is \frac{g}{8}, then the ratio of the masses \frac{m _{2}}{m _{1}} is :$ (1) $8 : 1$ (2) $5 : 3$ (3) $4 : 3$ (4) $9 : 7$ 9. $A body of mass 10 kg is moving with an initial speed of 20 m/s. The body stops after 5 s due to friction between body and the floor. The value of the coefficient of friction is: (Take acceleration due to gravity g = 10 m s^{- 2})$ (1) $0.2$ (2) $0.3$ (3) $0.5$ (4) $0.4$ 10. $"The uniform motion is possible when no frictional forces oppose" is the concept of$ (1) $The Greek thinker Aristotle$ (2) $The Scientist Newton$ (3) $The Scientist Copernicus$ (4) $The Scientist Galileo$ 11. $A block of mass 5 kg moving on a rough surface with a velocity of 4 ms^{- 1} is stopped by the friction in 2 seconds. Then the coefficient of friction between the contact surfaces is (Acceleration due to gravity = 10 ms^{- 2})$ (1) $0.4$ (2) $0.3$ (3) $0.5$ (4) $0.2$ 12. $A particle moving in the xy plane experiences a velocity dependent force F \to= k (v_{y} i^+ v_{x} j^) where V_{X} and v_{y} are the x and y components of its velocity v . If a is the acceleration of the particle, then which of the following statements is true for the particle?$ (1) $Quantity v \to \cdot a \to is constant in time$ (2) $Kinetic energy of particle is constant in time$ (3) $Quantity v \to \times a \to is constant in time$ (4) $F \to arises due to a magnetic field$ 13. $A block of mass m moving on a frictionless surface at speed V collides elastically with a block of same mass, initially at rest. Now the first block moves at an angle θ with its initial direction and has speed V_{1} . The speed of the second block after collision is$ (1) $V_{1}^{2} - V^{2}$ (2) $V^{2} - V_{1}^{2}$ (3) $V^{2} + V_{1}^{2}$ (4) $V - V_{1}$ 14. $A bob is whirled in a horizontal plane by means of a string with an initial speed of ω rpm . The tension is the string is T . If speed becomes 2 ω, while keeping the same radius, the tension in the string becomes [NEET 2024]$ (1) $T$ (2) $4 T$ (3) $\frac{T}{4}$ (4) $2 T$ 15. $A block has been placed on a inclined plane with the slope angle 6, block slides down the plane at constant speed. The coefficient of kinetic friction is equal to$ (1) $sin Θ$ (2) $cos Θ$ (3) $g$ (4) $tan Θ$ 16. $Consider a car moving along a straight horizontal road with a speed of 72 km/h If the coefficient of static friction between the tyres and the road is 0.5, the shortest distance in which the car can be stopped is (taking g=10m/ s^{2})$ (1) $30 m$ (2) $40 m$ (3) $72 m$ (4) $20 m$ 17. $The upper half of an incline plane with inclination φ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the the bottom if the coefficient of friction for the lower half is given by$ (1) $2 tan φ$ (2) $tan φ$ (3) $2 sin φ$ (4) $2 cos φ$ 18. $A car of mass 1000 kg negotiates a banked curve of radius 90 m on a friction less road. If the banking angle is 4 5^{o}, the speed of the car is$ (1) $20 m s^{- 1}$ (2) $30 m s^{- 1}$ (3) $5 m s^{- 1}$ (4) $10 m s^{- 1}$ 19. $Two blocks of masses W_{1} and W_{2} are suspended from the ends of a light string passing over a smooth fixed pulley. If the pulley is pulled up with an acceleration ' g', then the tension in the string will be$ (1) $\frac{4 W _{1} W _{2}}{W _{1} + W _{2}} g$ (2) $\frac{2 W _{1} W _{2}}{W _{1} + W _{2}} g$ (3) $\frac{W _{1} W _{2}}{W _{1} + W _{2}} g$ (4) $\frac{W _{1} W _{2}}{2 ( W _{1} + W _{2} )} g$ 20. $A conveyor belt is moving at a constant speed of 2 m s^{- 1} . A box is gently dropped on it. The coefficient of friction between them is μ = 0.5 . The distance that the box will move relative to belt before coming to rest on it, taking g = 10 m s^{- 2}, is$ (1) $0.4 m$ (2) $1.2 m$ (3) $0.6 m$ (4) $zero$ 21. $A bullet of mass 10 g moving horizontal with a velocity of 400 m / s strikes a wood block of mass 2 kg which is suspended by light inextensible string of length 5 m. As result, the centre of gravity of the block found to rise a vertical distance of 10 cm. The speed of the bullet after it emerges of horizontally from the block will be [NEET 2016]$ (1) $100 m / s$ (2) $80 m / s$ (3) $120 m / s$ (4) $160 m / s$ 22. $Consider a car moving on a straight road with a speed of 100 m/s. The distance at which car can be stopped is [µ_{k} = 0.5]$ (1) $100 m$ (2) $400 m$ (3) $800 m$ (4) $1000 m$ 23. $The coefficient of friction between object and substance, if we need to move an object of weight 150 N on a horizontal surface with a force of 75 N, is$ (1) $0.8$ (2) $0.5$ (3) $0.7$ (4) $0.9$ 24. $Calculate the maximum acceleration of a moving car so that a body lying on the floor of the car remains stationary. The coefficient of static friction between the body and the floor is 0.15 (g = 10 m s^{- 2}) . [NEET 2023]$ (1) $150 m s^{- 2}$ (2) $1.5 m s^{- 2}$ (3) $50 ms^{- 2}$ (4) $1.2 m s^{- 2}$ 25. $A person is driving a vehicle at uniform speed of 5 m s^{- 1} on a level curved track of radius 5 m . The coefficient of static friction between tyres and road is 0.1 . Will the person slip while taking the turn with the same speed? Take g = 10 m s^{- 2} . Choose the correct statement.$ (1) $A person will slip if v^{2} < 5 m s^{- 1} .$ (2) $A person will slip if v^{2} = 5 m s^{- 1} .$ (3) $A person will not slip if v^{2} > 10 m s^{- 1} .$ (4) $A person will slip if v^{2} > 5 m s^{- 1} .$ 26. $Which one of the following statements is incorrect?.$ (1) $Rolling friction is smaller than sliding friction.$ (2) $Limiting value of static friction is directly proportional to normal reaction.$ (3) $Frictional force opposes the relative motion.$ (4) $Coefficient of sliding friction has dimensions of length.$ 27. $A bullet enters a wooden block with velocity 120 m / s . The bullet travels 1.5 s in the block before its velocity reduces to zero due to resistance force which is proportional to the square root of the velocity. The distance travelled by the bullet in the wooden block is$ (1) $10 m$ (2) $60 m$ (3) $25 m$ (4) $None$ 28. $A body of mass 10 kg is kept on a rough horizontal surface of coefficient of friction 0.3 . If a horizontal force of 50 N is applied on the body, then the acceleration of the body is (Acceleration due to gravity = 10 ms^{- 2})$ (1) $5 ms^{- 2}$ (2) $2 ms^{- 2}$ (3) $3 ms^{- 2}$ (4) $1 ms^{- 2}$ 29. $The coefficient of static friction between the road and tyres of a car is 0.4 . The maximum permissible speed of the car is 10 ms^{- 1} on curved unbanked road. Then the maximum radius of curvature of the road is (acceleration due to gravity = 10 ms^{- 2})$ (1) $105 m$ (2) $25 m$ (3) $202 m$ (4) $30 m$ 30. $A bullet of mass 0.1 kg is fired on a wooden block to pierce through it, but it stops after moving a distance of 50 cm into it. If the velocity of bullet before hitting the wood is 10 m / s and it slows down with uniformdeceleration, then the magnitude of effective retarding force on the bullet is ’ x ’ N . The valueof ’ x ’ to the nearest integer is_____$