Two iron blocks of equal mass but with double surface area slide down an inclined plane with friction coefficient μ.If the first block with surface area A experience a frictional force f, then the second block with surface area 2A will experience a frictional force
f/2
f
2f
4f
A body is placed on an inclined plane and has to be pushed down.The angle made by the normal reaction with the vertical will be
equal to the angle of repose
equal to the angle of friction
less than the angle of repose
more than the angle of friction
The upper half of an inclined plane of inclination θ is perfectly smooth while the lower is rough.A body starting from rest at the top comes back to rest at the bottom,if the coefficient of friction for the lower half is given by
μ = sin θ
μ = cotθ
μ = 2 cosθ
μ = 2 tanθ
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 car turns a corner on a slippery road at a constant speed of 12 m/s. If the coefficient of friction if 0.4, the minimum radius of the arc is metre in which the car turns is
72
36
18
9
A 10 kg stone is suspended with a rope of breaking stength 30 kg wt.The minimum time in which the stone can be raised through a height 10 m starting from rest is (taking g = 10 N/kg):
0.5 seconds
1.0 seconds
√2 / √3 seconds
2.0 seconds
A 5000 kg rocket is set for vertical firing.The exhaust speed is 800 m/s and acceleration(a) of the rocket is 20 m/s2.The acceleration due to gravity is 10 m/s2.The amount of gas ejected per second is
127.5 kg/s
137.5 kg/s
185.5 kg/s
187.5 kg/s
Two trains A and B are running in the same direction on parallel tracks such that A is faster than B.If packets of equal weight are exchanged between the two, then
A will be retarded but B will be accelerated
A will be accelerated but B will be retarded
there will not be any change in the velocity of A but B will be accelerated.
there will not be any change in the velocity of B,but A will be accelerated.
A force of 100 N need to be applied parallel to a smooth inclined plane just to hold a body on it. The angle of inclination of the inclined plane is 300. How much horizontal force need to be applied to do the same?
50 N
87 N
100 N
115 N
A block is lying static on the floor.The maximum value of static frictional force on the block is 10 N.If a horizontal force of 8 N is applied to the block,what will be the frictional force on the block ?
2 N
18 N
8 N
10 N