JEE Main Physics Quiz: Laws Of Motion Set 2!

In the diagram shown the shaded block is fixed. The mass of block A is 4 kg and the coefficient of friction between the shaded block and block A is 1/4. What should be the maximum weight of the block b so that the whole system remains in the state of equilibrium?

• 10 N

• 40 N

• 20 N

• 15 N

During the motion of the bicycle, a force of friction is exerted by the ground on the two wheels of the bicycle. Which of the following statement is true in this context?

• Frictional force for the wheels of bicycle will depend on the motion of the wheels

• Frictional force will depend on the surface and the weight of bicycle and the person sitting on it

• Frictional force will act in the direction of the motion

• None of these

A passenger is traveling in a train moving at a speed of 50 m/s. Briefcase of the man is resting on the berth of the train. Suddenly the driver applies brakes due to which the speed of the train decreases at a speed of 15 m/s in 3 s. What should be the minimum coefficient of friction between the berth and the briefcase so that the briefcase doesn’t slide down? (take g = 10 m/s²)

• 0.1

• 0.5

• 0.2

• 2

An ant is slowly crawling up a hemispherical surface with negligible speed. The coefficient of friction between the ant and the surface is 2/3. If the line joining the ant and the center of the hemispherical surface subtends an angle ‘θ’ with vertical, then which of the following is true?

• Cot θ = 1.5

• Tan θ = 1.5

• Sec θ = 1.5

• Cosec θ = 1.5

In the diagram weight of A = 250 N, the weight of B = 150 N, the weight of C = 100 N. The value of the coefficient of friction between A & B is 0.7 and that is between B & C is 0.4 and between C and the ground, the coefficient of friction is 0.3. What should be the minimum value of force F so that any part of the system shown in the figure starts moving?

• 175 N

• 90 N

• 160 N

• 150 N

Which of the following statement is wrong about the friction?

• The formula f = μN tells us that the f and N are comparable as they are having these two quantities have the same direction

• Friction force can be zero, even though the surfaces in contact are rough

• If there is no relative motion between the two surfaces still there might be a friction force between the surfaces

• None of these

A block of mass 0.2 kg is held against a wall by applying a horizontal force of 6 N on the block. If the coefficient of friction between the block and the wall is 0.3, then what will be the value of frictional force acting on the block?

• 1.8 N

• 0.49 N

• 2.45 N

• 1.96 N

Two blocks A and B of different masses have velocities V_A and V_B respectively. A horizontal force F is acting on the block A. Coefficient of friction between A & B is μ and that of between B & ground is zero. If V_A = V_B then which among the following statement is correct?

• Friction on A supports its motion

• Friction on B supports its motion

• Both a & b

• None of these

A particle starts from point C with some initial velocity in the hemispherical vessel of radius ‘R’. Mass of the particle is ‘m’ and the coefficient of friction between the particle and the hemispherical surface is μ then what should be the value of initial velocity so that the particle starts falling after reaching the point B.