(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Now, suppose the student wishes to bring back some ice cream from the restaurant for her friends at school, but since it is such a hot day, the ice cream will melt away in the car in only 5 minutes. How fast will the student have to drive back to get the ice cream to her friends before it completely melts?

Knowns:

C=40mph(for these problems)

Time=5 minutes

Distance=7.5 miles

2. Relevant equations

Dt= change in time

p= proper interval

Dt-p= d/v

Dt-p=Dt/lambda or dt/sqrt(1-v^2/c^2)

3. The attempt at a solution

Dt-p=7.5m/40mph=.1875hr

.1875=(5minutes/60minutes per hour)/sqrt(1-v^2/40^2)

rearranging it becomes:

v=sqrt( -((.083hr/.1875hr)^2-1)*40^2)

answer I get is 35.8mph

The online homework tells me I am wrong either by sig figs or by bad rounding.

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# Time dilation and a car

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