What is the change in kinetic energy of an object that strikes a wall and rebounds with the same speed in the opposite direction?

What is the change in kinetic energy of an object that strikes a wall and rebounds with the same speed in the opposite direction?

• A. -mv²
• B. Zero
• C. 1/2mv²
• D. mv²

Answer: (B)

The change in kinetic energy of an object is determined by the difference between its initial kinetic energy and its final kinetic energy. When an object strikes a wall and rebounds with the same speed in the opposite direction, it maintains the same speed; however, the direction of its velocity changes. Kinetic energy is calculated using the formula \( KE = \frac{1}{2}mv^2 \). In this case, the initial kinetic energy before the collision is \( \frac{1}{2}mv^2 \) (moving in one direction) and the final kinetic energy after rebounding is also \( \frac{1}{2}mv^2 \) (moving in the opposite direction). Since both the initial and final kinetic energy values are equal, the difference, which denotes the change in kinetic energy, is: \[ \text{Change in KE} = KE_{final} - KE_{initial} = \frac{1}{2}mv^2 - \frac{1}{2}mv^2 = 0 \] Thus, the change in kinetic energy is zero, indicating that the object's energy state remains the same before and after the collision despite the reversal of direction.

The change in kinetic energy of an object is determined by the difference between its initial kinetic energy and its final kinetic energy. When an object strikes a wall and rebounds with the same speed in the opposite direction, it maintains the same speed; however, the direction of its velocity changes.

Kinetic energy is calculated using the formula ( KE = \frac{1}{2}mv^2 ). In this case, the initial kinetic energy before the collision is ( \frac{1}{2}mv^2 ) (moving in one direction) and the final kinetic energy after rebounding is also ( \frac{1}{2}mv^2 ) (moving in the opposite direction). Since both the initial and final kinetic energy values are equal, the difference, which denotes the change in kinetic energy, is:

[

\text{Change in KE} = KE_{final} - KE_{initial} = \frac{1}{2}mv^2 - \frac{1}{2}mv^2 = 0

]

Thus, the change in kinetic energy is zero, indicating that the object's energy state remains the same before and after the collision despite the reversal of direction.