A block of mass m is on an inclined plane of angle θ. The coefficient of friction between the block and the plane is μ and tanθ>μ. The block is held stationary by applying a force P parallel to the plane. The direction of force pointing up the plane is taken to be positive. As P is varied from P1 = mg(sinθ-μcosθ) to P2 = mg(sinθ+μcosθ), the frictional force f versus P graph will look like
A weight W rests on a rough horizontal plane. If the angle of friction be θ, the least force that will move the body along the plane will be
W cosθ
W tanθ
W cotθ
W sinθ
A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N on the block. If the co-efficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting on the block is
2.5 N
0.98 N
4.9 N
0.49 N
A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is
20 N
50 N
100 N
2 N
A heavy uniform chain lies on horizontal table top.If the coeffecient of friction between the chain and the table surface is 0.25,then the maximum friction of the length of the chain that can hang over one edge of the table is
20 %
25 %
35 %
15 %
The maximum velocity (in ms-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction 0.6 to avoid skidding is
60
30
15
25
If the normal force is doubled,then coefficient of friction is
halved
tripled
doubled
not changed
Friction is the result of
gravitational acceleration
molecular interaction
magnetic interaction
nuclear interaction
A marble block of mass 2 kg lying on ice, when given a velocity of 6 ms-1, is stopped by friction in 10 s. Then the coefficient of friction is
0.02
0.03
0.06
0.01
A block of metal of mass 2 kg is resting on a frictionless floor.It is struck by a jet releasing water at the rate of 1 kg/sec and at a speed of 5 m/s.What will be the initial acceleration of the block ?
3.5 m/s2
4.5 m/s2
2.5 m/s2
none of these
