What occurs to a body's speed when the net work is positive?

What occurs to a body's speed when the net work is positive?

• A. The body will slow down
• B. The body will maintain its speed
• C. The body will stop
• D. The body will speed up

Answer: (D)

When the net work done on a body is positive, it means that energy is being added to the system. According to the work-energy principle, the net work on an object is equal to the change in its kinetic energy. A positive net work indicates that the kinetic energy of the object is increasing. As kinetic energy increases, the speed of the body must also increase because kinetic energy is directly related to speed through the equation \( KE = \frac{1}{2} mv^2 \), where \( m \) is the mass and \( v \) is the speed of the object. Therefore, with positive net work, the speed of the body will increase, confirming the correct answer as a body will speed up. In contrast, if the net work were zero, the speed would remain unchanged, and if it were negative, the body would lose kinetic energy and slow down.

When the net work done on a body is positive, it means that energy is being added to the system. According to the work-energy principle, the net work on an object is equal to the change in its kinetic energy. A positive net work indicates that the kinetic energy of the object is increasing.

As kinetic energy increases, the speed of the body must also increase because kinetic energy is directly related to speed through the equation ( KE = \frac{1}{2} mv^2 ), where ( m ) is the mass and ( v ) is the speed of the object. Therefore, with positive net work, the speed of the body will increase, confirming the correct answer as a body will speed up.

In contrast, if the net work were zero, the speed would remain unchanged, and if it were negative, the body would lose kinetic energy and slow down.