Question

25 mr. allen’s class is watching a video on motion. he pauses the video and asks them to carefully examine the picture.
image of a truck (12 km/hr right), motorcycle (10 km/hr left), car (15 km/hr right), pedestrian (1 km/hr left), and a person on a bench
from whose perspective would the car have the greatest velocity?
a driver of the truck
b driver of the motorcycle
c pedestrian on the sidewalk
d person sitting on the bench

Explanation:

To determine from whose perspective the car has the greatest velocity, we analyze the relative motion:

• Truck driver (A): The truck moves at 12 km/hr right, the car at 15 km/hr right. Relative velocity: \( 15 - 12 = 3 \) km/hr right.
• Motorcycle driver (B): The motorcycle moves at 10 km/hr left (opposite to the car’s rightward motion). Relative velocity: \( 15 + 10 = 25 \) km/hr right (since velocities are in opposite directions, we add their magnitudes).
• Pedestrian (C) and Bench-sitter (D): Both are stationary (0 km/hr). The car’s velocity relative to them is 15 km/hr right.

The motorcycle driver’s frame of reference gives the highest relative velocity for the car (25 km/hr) because the motorcycle moves opposite to the car, increasing the relative speed.

Answer:

B. driver of the motorcycle