Coefficients of Friction
Trending Questions
Q. Two bodies of masses m1 and m2 are placed on a horizontal table with coefficient of friction μ and are joined by a spring. Initially, the spring has its natural length. If F is minimum force which, when continuously applied on m1, will make the other block m2 just move (k is the spring constant) and x is elongation in spring at that instant


- x=μm2gk
- x=2μm2gk
- F=μm2g+μm1g2
- F=μm1g+μm2g2
Q. A circular road of radius 1000 m has banking angle 45∘. The maximum safe speed of a car having mass 2000 kg will be, if the coefficient of friction between tyre and road is 0.5
- 99 m/s
- 172 m/s
- 124 m/s
- 86 m/s
Q. The coefficient of friction can never be more than 1.
- False
- True
Q. For any given pair of surfaces, the coefficient of friction is maximum in case of limiting friction.
- False
- True
Q. The coefficient of friction has no unit.
- False
- True
Q. 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 300, the box starts to slip and slides 4 m down the plank in 4 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively

- 0.4 and 0.3
- 0.6 and 0.6
- 0.6 and 0.5
- 0.5 and 0.6
Q.
A block pressed against the vertical wall is in equilibrium. The minimum coefficient of friction is
- 0.4
- 0.2
- 0.5
- None of these
Q. For a body on a horizontal surface, coefficients of static and kinetic frictions are 0.4 and 0.2, respectively. When the body is in uniform motion on the surface, a horizontal force equal in magnitude to limiting friction is applied on it. The acceleration produced is


- 0.4 g
- 0.1 g
- 0.2 g
- 0.6 g
Q. A block begins to slide down a rough inclined plane of angle 45∘ and moves 1 m in 4√2 s. What is the coefficient of friction μ, between the plane and the block?
(Take g=10 m/s2)
(Take g=10 m/s2)
- 0.6
- 0.8
- 0.5
- 0.4
Q. A box of mass 8 kg is placed on a rough inclined plane of angle θ with horizontal. Its downward motion can be prevented by applying an upward pull F and it can be made to slide upwards by applying a force 2F. The coefficient of friction between the box and the inclined plane is
- tanθ3
- 3tanθ
- tanθ2
- 2tanθ