Question

When is the net force on an object equal to zero? (4 points)
A.When the object is in motion
B.When the object is changing direction
C.When the forces acting on the object are balanced
D.When inertia is not present

Answer 1

Correct answer is option C. In a balanced force the resultsnt of all forces acting on the body is zero

Answer 2

The net force on an object is equal to zero when the forces acting on the object are balanced. (option C.)

• Let us consider each situation.

A.When the object is in motion.

• When an object is in motion, a force is required to keep it in motion if it is not in an isolated system.
• In any plane, some friction is present. Thus, a force is required to overcome this friction, or the object will come to a stop.
• Hence, the forces acting on the object are not equal to 0.

B.When the object is changing direction

• When an object is changing direction, a force is required to overcome its inertia of direction.
• The object tends to stay in the same direction, thus a force has to be applied against its direction to change it.
• So, the forces acting on it are not 0.

C.When the forces acting on the object are balanced

• When the forces acting on the object are balanced, it is in equilibrium.
• Balanced forces imply that all forces, or their effective values, are equal and opposite to each other in magnitude and direction.
• Since all forces cancel each other, so the object has no effective force acting on it.
• Such an object could be at rest or in motion.
• Thus the net force on the object is 0.

D.When inertia is not present

• The absence of inertia implies that the mass of the body is 0 as inertia is the measure of mass.
• In such a situation, the object will have infinite acceleration and will continue to be in its state of rest or motion forever.

• Since this is practically impossible, thus it cannot be the correct answer.

Hence, option C. When the forces acting on the object are balanced is the correct option.