Question

6 felipe is on a train going south at 30 meters per second. at one point, he passes a train that is traveling north at 24 meters per second. from felipes frame of reference, what is the velocity of the northbound train?
1.25 m/s
6 m/s
24 m/s
54 m/s

Explanation:

Step1: Define the positive direction

Let's assume the south - direction as positive. So Felipe's velocity \(v_{F} = 30\ m/s\), and the north - bound train's velocity \(v_{N}=- 24\ m/s\) (negative because it is in the opposite direction of the assumed positive direction).

Step2: Calculate the relative velocity

The relative velocity \(v_{rel}\) of the north - bound train with respect to Felipe is given by the formula \(v_{rel}=v_{N}-v_{F}\).
Substitute the values: \(v_{rel}=-24 - 30=-54\ m/s\). The magnitude of the relative velocity (since velocity is a vector and we are asked for the speed in terms of magnitude from the frame of reference, considering direction in the sign but magnitude as the answer value) is \(54\ m/s\).

Answer:

54 m/s