Friction is the result of
gravitational acceleration
molecular interaction
magnetic interaction
nuclear interaction
An iron block of sides 5 cm x 8 cm x 15 cm has to be pushed along the floor.The force required will be minimum when the surface in contact with ground is
8 cm x 15 cm surface
8 cm x 5 cm surface
5 cm x 15 cm surface
force is the same for all surfaces
A car of mass m is moving with momentum p.If μ be the coeffecient of friction between the tyres and the road, what will be stopping distance due to friction alone ?
p2 / 2μg
p2 / 2mμg
p2 / 2m2μg
p2 / 2mg
To avoid slipping while walking on ice one should take smallest steps because of the
larger friction
larger normal reaction
smaller friction
smaller normal reaction
A block of mass 10 kg is placed on a rough horizontal surface whose coeffecient of friction is 0.5.If a horizontal force of 100 N is applied on it,then acceleration of block will be :
10 m/s2
5 m/s2
15 m/s2
0.5 m/s2
If the normal force is doubled,then coefficient of friction is
halved
tripled
doubled
not changed
Assertion (A): Frictional forces are conservative forces.Reason(R): Potential energy can be associated with frictional forces.
Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not correct explanation of A
A is true,but R is false
Both A and R are false
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
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 car turns a corner on a slippery road at a constant speed of 12 m/s. If the coefficient of friction is 0.4, the minimum radius of the arc in metre in which the car turns is
72
36
18
9
