In which of the following cases more friction is desirable?
Movement of piston in a cylinder.
Braking of a vehicle.
Running on a track.
All of the above.
A person is moving on a rough horizontal surface towards east. The direction of friction force is towards
West
East
North
South
A streamlined body
Increases friction.
Reduces friction.
Decreases weight.
Increases weight.
Friction is force. How is friction caused?
One surface moving.
Two surfaces being pushed together.
Two surfaces being rubbed together.
Two surface being pulled apart.
A meteor burns up on entering earth’s atmosphere due to
Stmospheric pressure.
Heat of the earth.
Solar radiation.
Excessive friction.
The application of decreasing friction include
I. Ball bearing used in moving parts of a machine.
II. The streamlined shape of an aircraft.
III. The layer of air between the hull of a hovecraft and the ground.
I and II only
II and III only
III and I only
All of these
Special kinds of grooves are made in automobile tyres. This is done in order to
Reduce Friction.
Increases the speed of rotation of the tyres.
for more style
Which of the following statements is correct about frictional force?
It exists only for moving bodies.
It exists only for bodies which are at rest
It exists for both moving and non-moving bodies
None of these
Wheel and axle help to move objects with a very little force. This is because
Rolling friction > Sliding friction.
Sliding friction > Rolling friction.
Rolling friction = Sliding friction.
Rolling friction + Sliding friction = 0
If we apply a force to a body which is in contact with the surface of another body and if the body does not move, then the force of friction is
Static friction.
Limiting friction.
Dynamic friction.
Sliding friction.
