Question

A bus is moving down a road at a velocity of +30 m/s. A car is moving in the same direction at a velocity of +35 m/s. Relative to the car, what is the velocity of the bus?

Answer 1

subtract putting bus velocity first 30-35=-5m/s
If you are sitting in the car it seems as if the bus moves backwards at 5m/s

Answer 2

5 m/s.

Step-by-step explanation:

Here we need to apply the concept of relative speed in one dimension.

When we talk about relative speed, we refer to the speed of an object from the point of view of another moving object. Like this proble, we have to moving objects in the same direction, and we want to know the the speed of the bus relative to the car, that is, from the point of view of the car.

So, we can define relative speed as

`V_(relative)=V_(car)-V_(bus)`

We know that

`V_(car)=35m/s \\V_(bus)=30m/s`

Replacing each velocity, we have

`V_(relative)=V_(car)-V_(bus)=35m/s-30m/s=5m/s`

Therefore the velocity of the bus, relative to the car, is 5m/s.