A Level Physics Practice Exam

What happens to the kinetic energy of the gymnast when they reach their highest point above position B?

1. Kinetic energy increases

2. Kinetic energy remains constant

3. Kinetic energy decreases

4. Kinetic energy becomes negative

The correct answer is: Kinetic energy decreases

As the gymnast ascends to their highest point above position B, they are moving against the force of gravity, which requires work to be done on them in order to gain height. During this ascent, the kinetic energy of the gymnast decreases because some of the kinetic energy is being transformed into potential energy. At the highest point, the gymnast has reached their maximum height, and their velocity is momentarily zero, indicating that their kinetic energy is at its lowest point at that instant. The kinetic energy is given by the expression \( KE = \frac{1}{2} mv^2 \), where \( m \) is mass and \( v \) is velocity. Since the velocity of the gymnast decreases as they rise, their kinetic energy must also decrease. Thus, the correct answer highlights that the gymnast's kinetic energy decreases as they reach the highest point in their trajectory.