Q:

If I were to sit on my front lawn and look up and see a plane. How could I determine how fast it is moving if I use two telephone wires? The wires would be some distance apart, but one above the other. Thanks John

- John

Burlington, VT

- John

Burlington, VT

A:

John -

Well, I won't do your homework for you, but here's some help... In order to figure out how fast something is going, you need to know the distance that it goes in a certain amount of time. One way to do this is if you have 2 locations and the amount of time it takes to get from one to another. Try drawing a picture with yourself, the telephone lines, and the plane in it. Draw the plane in a number of different positions as it moves by overhead. Think about where it looks like the plane is relative to the phone lines. Can you use geometry to calculate the distance between 2 positions? You will probably need to know the plane's altitude or the distance it is from you.

-Tamara

Well, I won't do your homework for you, but here's some help... In order to figure out how fast something is going, you need to know the distance that it goes in a certain amount of time. One way to do this is if you have 2 locations and the amount of time it takes to get from one to another. Try drawing a picture with yourself, the telephone lines, and the plane in it. Draw the plane in a number of different positions as it moves by overhead. Think about where it looks like the plane is relative to the phone lines. Can you use geometry to calculate the distance between 2 positions? You will probably need to know the plane's altitude or the distance it is from you.

-Tamara

*(published on 10/22/2007)*