Problema Solution
While walking between gates at an airport, you notice a child running along a moving walkway. Estimating that the child runs at a constant speed of 2.7 m/s relative to the surface of the walkway, you decide to try to determine the speed of the walkway itself. You watch the child run on the entire 22-m walkway in one direction, immediately turn around, and run back to his starting point. The entire trip takes a total elapsed time of 32 s. Given this information, what is the speed of the moving walkway relative to the airport terminal?
Answer provided by our tutors
let
w = the speed of the moving walkway relative to the airport terminal
v = 2.7 m/s at the child's speed relative to the surface of the walkway
d = 22 m the distance in one direction
t = 32 s the total time of the trip of the child
(v + w) = the speed of the child relative to the airport terminal running along the moving walkaway
(v - w) = the speed of the child relative to the airport terminal running back (against the moving walkaway)
since speed = distance/time => time = distance/speed
d/(v + w) + d/(v - w) = t
22/(2.7 + w) + 22/(2.7 - w) = 32
by solving the equation we find and consider the positive roots
w = 1.89 m/s
click here to see the step by step solution of the equation
the speed of the moving walkway relative to the airport terminal is 1.89 m/s.