Which law is illustrated when a bowling ball hits pins and they fly backwards?

Which law is illustrated when a bowling ball hits pins and they fly backwards?

• A. Newton's First Law of Motion
• B. Newton's Second Law of Motion
• C. The Law of Inertia
• D. Newton's Third Law of Motion

Answer: (A)

Inertia, the tendency of an object to keep doing what it’s doing unless a net external force acts, is the key idea. The pins start at rest, and when the bowling ball strikes them, the contact force from the ball on the pins is an external force that changes their state of motion. That net force gives the pins backward acceleration, so they move in the opposite direction. This demonstrates how motion changes only because an external force acts on the object, which is exactly Newton’s First Law. (As a side note, there’s a reaction force on the ball from the pins as well, but the observable backward motion is the result of the net external force acting on the pins.)

Inertia, the tendency of an object to keep doing what it’s doing unless a net external force acts, is the key idea. The pins start at rest, and when the bowling ball strikes them, the contact force from the ball on the pins is an external force that changes their state of motion. That net force gives the pins backward acceleration, so they move in the opposite direction. This demonstrates how motion changes only because an external force acts on the object, which is exactly Newton’s First Law. (As a side note, there’s a reaction force on the ball from the pins as well, but the observable backward motion is the result of the net external force acting on the pins.)