Question

1. look at the four vehicles.

image of a truck, car, pickup truck, and motorcycle
the vehicles are all moving at the same speed along a road. which of these statements is correct?
a. the motorcycle has the most kinetic energy because it is the vehicle with the least mass.
b. all the vehicles have the same kinetic energy because they are all moving at the same speed.
c. the delivery truck has the greatest kinetic energy because its mass is greater than that of the other vehicles.
d. the delivery truck has the greatest kinetic energy because it has the most tires in contact with the pavement.

Explanation:

To determine the correct statement about kinetic energy (\(KE\)) of the vehicles, we use the formula for kinetic energy: \( KE = \frac{1}{2}mv^2 \), where \( m \) is mass and \( v \) is speed. All vehicles have the same speed (\(v\) is constant). Kinetic energy depends on mass and speed. Since speed is the same, the vehicle with the greatest mass will have the greatest kinetic energy.

• Option A: A motorcycle has a small mass. From \( KE = \frac{1}{2}mv^2 \), smaller mass (with same speed) means smaller \( KE \), so A is wrong.
• Option B: Since masses of vehicles are different (truck, car, pickup, motorcycle have different masses), and \( KE \) depends on mass, their \( KE \) can't be the same. So B is wrong.
• Option C: The delivery truck has a greater mass than the other vehicles (car, pickup, motorcycle). With same speed, using \( KE = \frac{1}{2}mv^2 \), greater mass means greater \( KE \). So C is correct.
• Option D: Number of tires in contact with the pavement (friction - related) does not determine kinetic energy. Kinetic energy depends on mass and speed, not tire contact. So D is wrong.

Answer:

C. The delivery truck has the greatest kinetic energy because its mass is greater than that of the other vehicles.