# Maximum Push Using Friction

## Trending Questions

**Q.**A block rests on a rough incline plane making an angle of 30∘ with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg ) is (take g=10 m/s2)

- 2.5
- 4.0
- 2.0
- 1.6

**Q.**A block of mass 2 kg is put on a rough horizontal surface having coefficient of friction 0.5. The acceleration of block and frictional force acting on block if F=5 N is (Take g=10 m/s2)

- 52 m/s2, 10 N
- 0 m/s2, 5 N
- 0 m/s2, 10 N
- 5 m/s2, 5 N

**Q.**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)

- 0.2 kg
- 0.4 kg
- 2.0 kg
- 4.0 kg

**Q.**A block is moving on an inclined plane making an angle 45∘ with the horizontal and the coefficient of friction is μ. The force required to just push it up the inclined plane is 3 times the force required to just prevent it from sliding down. If we define n=10μ, then n is

- 2
- 6
- 4
- 5

**Q.**Find the minimum value of coefficient of friction between the 4 kg block and the surface for the system to be at rest for the figure shown, (Block A=4 kg and block B=3 kg)

- 0.4
- 0.5
- 0.6
- 0.75

**Q.**A car starts from rest to cover a distance s. The coefficient of friction between the road and the tyres is μ. The minimum time in which the car can cover the distance is proportional to

- μ
- 1μ
- √μ
- 1√μ

**Q.**A body of mass 10 kg is lying on a rough plane inclined at an angle of 30∘ to the horizontal and the co-efficient of friction is 0.5. The minimum force required to pull the body up the plane is (g=9.8 m/s2)

- 914 N
- 91.4 N
- 9.14 N
- 0.914 N

**Q.**A block of mass 5 kg is kept over a rough horizontal surface. A time varying force acts on it along the horizontal given by F = 2t. The block starts slipping at t = 2.5 s and its acceleration at t = 3 s is 0.4 m/s2. The summation of coefficients of static and kinetic friction is (take g=10 ms−2)

**Q.**A block of mass 1 kg is placed on a rough horizontal surface connected by a light string passing over two smooth pulleys as shown. Another block of 1 kg is connected to the other end of the string. The acceleration of the system is (coefficient of friction for rough horizontal surface is μ=0.2)

- 0.8 g
- Zero
- 0.4 g
- 0.5 g

**Q.**For the arrangement shown in figure, the tension in the string to prevent it from sliding down is

- 64 N
- 6 N
- 0.4 N
- None of these

**Q.**A block of mass 10 kg is pressed against a vertical wall. If the coefficient of friction between the wall and the block is 0.2, then what is the minimum force that should be applied on the block so that does not fall to the ground?

- 600 N
- 500 N
- 400 N
- 555.5 N

**Q.**A uniform rope of length l lies on a table. If the coefficient of friction is μ, then the maximum length l1 of the hanging part of the rope which can overhang from the edge of the table without sliding down is

- lμ
- 1(μ+1)
- μl(μ+l)
- μl(μ−1)

**Q.**Statement I: It is easier to pull a heavy object than to push it on a level ground.

Statement II: The magnitude of frictional force depends on the nature of the two surfaces in contact.

- Both Statements are true and Statement II is the correct explanation for Statement I.
- Both Statements are true and Statement II is not the correct explanation for Statement I.
- Statement I is true and Statement II is false.
- Statement I is false and Statement II is true.

**Q.**A time dependent force F=3t (F in Newtons and t in seconds) acts on three blocks m1, m2 and m3 kept in contact on a rough ground as shown. Coefficient of friction between blocks and ground is 0.4. If m1, m2 and m3 are 3 kg, 2 kg and 1 kg respectively, the time after which the blocks start to move is (g=10 ms−2)

- 4 sec
- 8 sec
- 83 sec
- 43 sec

**Q.**The coefficient of friction between the tyres and road is 0.4. The minimum distance covered before attaining a speed of 8 ms−1 starting from rest is nearly (g=10 m/s2)

- 8.0 m
- 4.0 m
- 10.0 m
- 16.0 m

**Q.**A piece of ice starting from rest slides down a rough 45∘ incline in twice the time it takes to slide down a frictionless 45∘ incline. What is the coefficient of friction between the ice and incline?

- 0.50
- 0.75
- 0.40
- 0.25

**Q.**A block of mass 15 kg is resting on a rough inclined plane as shown in figure. The block is tied up by a horizontal string which has a tension of 50 N. Calculate the coefficient of friction between the block and inclined plane. Consider g=10 ms−2

**Q.**A block is placed on a rough horizontal plane. A time dependent horizontal force F=kt acts on the block. Here k is a positive constant. Acceleration-time graph of the block is

**Q.**A solid uniform disc of mass m rolls without slipping down an inclined plane with an acceleration a. The frictional force on the disc due to surface of the plane is

- 2 ma
- 32 ma
- ma
- 12 ma

**Q.**Two blocks A and B are arranged as shown in the figure. The mass of block A is 10 kg. The coefficient of friction between block A and the horizontal plane is 0.2. The minimum mass of block B to start motion will be

- 5 kg
- 0.2 kg
- 10 kg
- 2 kg

**Q.**A mass M is suspended from a massless spring. An additional mass m stretches the spring further by a

distance x. The combined mass will oscillate with a period

- 2π√{(M+m)xmg}
- 2π√{mg(M+m)x}

- π2√{mg(M+m)x}
- 2π√{(M+m)mgx}

**Q.**A body of mass m rests on a horizontal surface. The coefficient of friction between the body and the surface is μ. If the mass is pulled by a force P as shown in the figure, the limiting friction between the body and surface will be

- μ[mg−(P2)]
- μmg
- μ[mg+(P2)]
- μ[mg−(√3P2)]

**Q.**A person wants to drive on the vertical surface of a large cylindrical wooden 'well' commonly known as death well' in a circus. The radius of the well is R and the coefficient of friction between the tyres of the motorcycle and the wall of the well is μs. The minimum speed, the motorcycle must have in order to prevent slipping, should be

- √μsRg
- √μsgR
- √Rgμs
- √Rμsg

**Q.**A block of mass 1 kg is kept on a rough inclined plane of angle 30o. Find the frictional force acting on the block. Given coefficient of friction μ=0.8

- 6.7 N
- 4.9 N
- 10 N
- Zero

**Q.**A block of mass m is placed on the top of another block of mass M as shown in the figure. The coefficient of friction between them is μ. Maximum acceleration of M such that M and m move together is (there is no friction between ground and M)

- μg
- gμ
- gμ2
- μ2g

**Q.**The brakes of a car moving at 20 m/s along a horizontal road are suddenly applied and it comes to rest after travelling some distance. If the coefficient of friction between the tyres and the road is 0.90, and it is assumed that all four tyres behave identically, find the shortest distance the car would travel before coming to a stop.

- 2.22 m
- 11.35 m
- 22.2 m
- 4.54 m

**Q.**The pulley is given an acceleration a0=2 m/s2 starting from rest. A cable is connected to a block A of mass 50 kg as shown. Neglect the mass of the pulley. If μ=0.3 between the block and the floor, then the tension in the cable is:

- 200 N
- 250 N
- 300 N
- 350 N

**Q.**The tension T in the string shown in figure is

- Zero
- 35√3 N
- 50 N
- (√3−1)50 N

**Q.**The block B has a mass of 10 kg. The coefficient of friction between block B and the surface is μ=0.5. Determine the acceleration of the block A of mass 16 kg. Neglect the mass of the pulleys and cords. (Take g=10 m/s2).

- Zero
- 1 m/s2
- 2 m/s2
- None of these

**Q.**A block of mass 2 kg is put on a rough horizontal surface having coefficient of friction 0.5. The acceleration of block and frictional force acting on block if F=5 N is (Take g=10 m/s2)

- 52 m/s2, 10 N
- 0 m/s2, 5 N
- 0 m/s2, 10 N
- 5 m/s2, 5 N