# Proper Time (Relativity)

• deenuh20

## Homework Statement

A plane flies with a constant velocity of 208 m/s. The clocks on the plane show that it takes exactly 2.00 hours to travel a certain distance. Calculate how much longer or shorter than 2.00 h this flight will last, according to clocks on the ground. ________s

## Homework Equations

delta t = delta t(not) / (1-v^2/c^2)

## The Attempt at a Solution

Because the velocity of the plane is very low, I used the binomial expansion: delta t = delta t(not)*[1 + 1/2*[208m/s / 3x10^8 m/s]^2]. When I worked it out and solved for delta t, I got .999, which I then added to the 7200s ( 2 hours). I know that the time according to the ground clocks will be longer, but I think there's a math error somewhere which is preventing me from understanding and getting the answer. Any help is appreciated. Thank you!

What are delta(t) and delta(t0) (nought not not) supposed to mean? Get rid of the deltas in that formula and realize delta(t)=t-t0. And you won't get .999 unless your calculator only has three digits of precision.