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Definition of Force Inertia and First Law

Question 1:

Consider the following two statements:

(A) Linear momentum of a system of particles is zero

(B) Kinetic energy of a system of particles is zero

Then:

1. A does not imply B and B does not imply A

2. A implies B but B does not imply A

3. A does not imply B but B implies A

4. A implies B and B implies A

View Answer

When kinetic energy of the system is zero, speed of objects will be zero so momentum will always be zero.

Whereas momentum being a vector quantity may be zero when directions of velocities cancel each other. so speed and kinetic energy may of may not be zero when momentum is zero

Question 2:

Which of the following option is correct regarding given statements :-
(I) It is possible for an object to have motion in the absence of forces on the object.
(II) It is possible to have forces on an object in the absence of motion of the object.

1. Only (I) is correct

2. Only (II) is correct

3. Both (I) & (II) are correct

4. neither (I) nor (II) is correct

View Answer

Statement I is correct because in absence of force object can move with constant velocity.

Statement II is correct because if many forces act on an object such that resultant is zero, the object will be in static equilibrium

Question 3:

An object experiences no acceleration which of the following can NOT be true for the object

1. A single force acts on the object

2. No forces act on the object

3. Forces act on the object, but the forces cancel

4. All of the above

View Answer

If only one force acts on the object it will be the net force. So the object will accelerate and it can't be at rest