Question

A bus is traveling at 60 miles/hour east. Determine the velocity of the following objects using the bus as the frame of reference:

• A car traveling at 60 miles/hour east?
• A truck traveling at 65 miles/hour west:?

Answer 1

a) v'=0 , B) v'= 125 miles/h

Step-by-step explanation:

This is a relative speed exercise, the speed of a body is

v ’= v - u

where v is the speed with respect to the Earth and u the speed of the reference frame with respect to which we want to calculate

a) with respect to a car traveling east at u = 60 miles / h

v ’= 60 -60

v ’= 0

with respect to this vehicle the speed of the car is zero

b) with respect to a truck traveling west at u = -65 miles / h

v = 60 - (-65)

v = 125 miles / h