A tennis ball is dropped down a stairwell.
Which statement BEST describes the energy of the tennis ball?
A. The tennis ball’s kinetic energy decreases as it falls to the ground.
B. The tennis ball has the most potential energy just before it is dropped.
C. The tennis ball has the most kinetic energy as soon as it is dropped.
D. The tennis ball’s potential energy increases as it falls to the ground.
C. The tennis ball has the most kinetic energy as soon as it is dropped.
E. The tennis ball is filled with potential for a hilarious bounce. Just wait and see!
C. The tennis ball has the most kinetic energy as soon as it is dropped.
Explanation: When the tennis ball is dropped, it starts to accelerate due to the force of gravity. As it accelerates, its velocity increases, and therefore its kinetic energy increases. The potential energy of the tennis ball will be converted into kinetic energy as it falls.
To determine the best answer, we need to understand the concepts of kinetic energy and potential energy.
Kinetic energy is the energy of an object in motion. It depends on the mass and velocity of the object. The formula for kinetic energy is KE = 0.5 * mass * velocity^2.
Potential energy is the stored energy that an object possesses due to its position or state. In the case of gravitational potential energy, it depends on the height and mass of the object. The formula for gravitational potential energy is PE = mass * gravity * height.
Now let's evaluate each statement:
A. The tennis ball’s kinetic energy decreases as it falls to the ground.
This statement is incorrect because as the tennis ball falls, its velocity increases, which means its kinetic energy actually increases.
B. The tennis ball has the most potential energy just before it is dropped.
This statement is correct. Since potential energy depends on height, the tennis ball has the highest potential energy just before it is dropped because it is at its highest position.
C. The tennis ball has the most kinetic energy as soon as it is dropped.
This statement is incorrect. While the tennis ball gains kinetic energy as it falls, its kinetic energy is not instantly at its highest as soon as it is dropped.
D. The tennis ball’s potential energy increases as it falls to the ground.
This statement is incorrect. As the tennis ball falls, its height decreases, and therefore its potential energy decreases.
Therefore, the best answer is B. The tennis ball has the most potential energy just before it is dropped.