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aft_lizard01
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Homework Statement
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
Homework Equations
Dt= change in time
p= proper interval
Dt-p= d/v
Dt-p=Dt/lambda or dt/sqrt(1-v^2/c^2)
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.