According to Newton's $1^{\text{st}}$ and $2^{\text{nd}}$ Laws, why does the bowling ball continue to move after Dr. Hewitt lifts it and gives it a push?

• A. Because the ball gains energy from the air around it, causing it to accelerate indefinitely.
• B. Because an object in motion remains in motion with constant velocity unless acted upon by a net external force, so the ball keeps moving due to its inertia.
• C. Because the force of gravity causes the ball to move horizontally after being pushed.
• D. Because Newton's $3^{\text{rd}}$ Law states that every action has an equal and opposite reaction, so the ball moves forward as a reaction to Dr. Hewitt's push.

Answer: (B)

Verified step by step guidance

1. Recall Newton's 1st Law of Motion, which states that an object at rest stays at rest and an object in motion stays in motion with the same velocity unless acted upon by a net external force. This property is called inertia.
2. Understand that when Dr. Hewitt lifts and pushes the bowling ball, he applies an external force that changes the ball's state from rest to motion, giving it a certain velocity.
3. Once the ball is moving, if no other net external forces (like friction or air resistance) act significantly on it, the ball will continue moving at a constant velocity due to its inertia.
4. Newton's 2nd Law relates force, mass, and acceleration by the equation \(\ F = m \times a \ \). Since after the push the net external force in the horizontal direction is zero, the acceleration is zero, so the velocity remains constant.
5. Therefore, the ball continues to move after being pushed because of its inertia, maintaining its velocity until another force acts upon it.