Consider a car moving along a straight horizontal road with a speed of 72 km/hr.If the coeffecient of static friction between the tyres and the road is 0.5,the shortest distance in which the car can be stopped is
(Take g = 10 m/s2)
30 m
40 m
72 m
20 m
When two surfaces are coated with lubricant,then they
stick to each other
slide upon each other
roll upon each other
none of these
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
A drum of radius R and mass M ,rolls down without slipping along an inclined plane of angle θ.The frictional force
converts translational energy to rotational energy
dissipates energy as heat
decreases the rotational motion
decreases the rotational and translational motion
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
When a bicycle is in motion, the force of friction exerted by ground on the two wheels is such that, it acts
In the backward direction on the front wheel and in the forward direction on the rear wheel.
In the forward direction on the front wheel and in the backward direction on the rear wheel.
In the backward direction on both the front and the rear wheels.
In the forward direction on both the front and the rear wheels.
A block of 10 kg is pulled at a constant speed on a rough horizontal surface by a force of 20 N.Find the co- effecient of kinetic friction .Given that g = 10 m/s2 .
0.2
0.5
0.85
0.7
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
Which of the following is the dimension of coefficient of friction?
[MLT-2]
[M0L0T0]
[M2LT-2]
[M2LT]
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
