Question

what is true about the mechanical energy of a car traveling at a high speed compared to a car moving at a lower speed? a. it has no mechanical energy. b. it has less mechanical energy. c. it has the same mechanical energy. d. it has more mechanical energy.

Explanation:

Step1: Recall the formula for mechanical energy

Mechanical energy \(E = E_{k}+E_{p}\). Assuming the car is on a horizontal road (\(E_{p}\) due to height is constant if we take the road - level as the reference), and \(E_{k}=\frac{1}{2}mv^{2}\).

Step2: Analyze the effect of speed on kinetic energy

Since \(E_{k}=\frac{1}{2}mv^{2}\), when the speed \(v\) decreases (car is moving at a lower speed), the kinetic energy \(E_{k}\) decreases. As \(E_{p}\) (assuming no - height change) is constant, the total mechanical energy \(E = E_{k}+E_{p}\) decreases.

Answer:

B. It has less mechanical energy.