A force that sets an object into motion is a. Balanced b. friction c. unbalanced d. inertia
The correct answer and explanation is:
Correct Answer: c. unbalanced
Explanation (300 words):
To understand why the correct answer is unbalanced, we need to look at Newton’s laws of motion, especially his First Law, which states:
“An object at rest stays at rest, and an object in motion stays in motion with the same speed and direction unless acted upon by an unbalanced force.”
This means that in order to change the motion of an object—either to start it moving, stop it, or change its direction—an unbalanced force must act on it.
Let’s briefly examine the other options to understand why they are incorrect:
- a. Balanced force:
Balanced forces are equal in size and opposite in direction. When forces on an object are balanced, they cancel each other out and do not cause a change in motion. For example, a book resting on a table experiences balanced forces (gravity pulling it down and the table pushing it up), so it remains at rest. - b. Friction:
Friction is a resistive force that acts opposite to the direction of motion. Rather than setting an object into motion, friction opposes motion. It tries to stop or slow down moving objects. - d. Inertia:
Inertia is not a force. It is a property of matter that resists changes in motion. A stationary object stays at rest, and a moving object keeps moving in a straight line unless acted upon by an external force. Inertia explains why objects resist changes in motion, but it doesn’t cause motion.
Conclusion:
Only unbalanced forces can change the motion of an object. If an object starts moving from rest, it’s because an unbalanced force acted on it—overcoming inertia and any opposing forces like friction. Therefore, the correct and most scientifically accurate answer is c. unbalanced.