Laws Of Motion

Physics
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A ball of mass 'm' moves normal to a wall with a velocity 'u' and rebounds with a velocity 'v'. The change in momentum of the ball is (surface of the wall is smooth):

A
towards the wall
B
towards the wall
C
away from the wall
D
away from the wall
Easy
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Which of following Newton's laws reveals the underlying symmetry in the forces that occur in nature?

A
First law
B
Second law
C
Third law
D
Law of gravitation
Easy
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When a moving body is suddenly stopped, then:

A
Frictional force increases.
B
Friction force remains same as it was while the car was moving.
C
Friction force reduces but has a non zero value.
D
Frictional force reduces to zero as it is a self adjusting force.
Easy
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When a body is in equilibrium, which of the following must be true ?

A
There is no force acting on it.
B
The sum of all the forces acting on it must be zero.
C
The sum of all the forces acting on it is not equal to zero.
D
There are exactly two forces acting on the body.
Easy
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Impulse is equal to

A
momentum
B
change in momentum
C
rate of change of momentum
D
rate of change of force
Easy
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Assertion

When a bus starts suddenly, a person standing in it falls backwards.

Reason

It is due to inertia of rest.

A
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C
Assertion is correct but Reason is incorrect
D
Assertion is incorrect but Reason is correct
Easy
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A stone tied to a string is rotated in a vertical circle. The minimum speed with which the stone has to be rotated in order to complete the circle :

A
decreases with increasing the mass of the stone
B
is independent of the mass of the stone
C
decreases with increasing the length of the string
D
is independent of the length of the string
Easy
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In which of the following cases the net force is not equal to zero?

A
A kite skillfully held stationary in the sky.
B
A ball falling freely from a height.
C
A helicopter hovering above the ground.
D
A cork floating on the surface of water.
Easy
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