Question 194611
1. At a height of h meters, you can see V kilometers to the horizon. These numbers are related by the equation V=3.5sqrt(h). A person can see 364 km to the horizon from an airplane window. How high is the airplane?
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The problem gives you V (364) you just need to find h:
{{{364=3.5sqrt(h)}}}
{{{104=sqrt(h)}}}
{{{10816 = h}}}
The airplane is 10816 meters high.
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2. The formula r=2sqrt5L can be used to approximate the speed r, in miles per hour, of a car that has left skid marks of length L, in feet. How far will a car skid at 50 mph?
{{{50 = 2 sqrt(5L)}}}
{{{25 = sqrt(5L)}}}
{{{625 = 5L }}}
{{{125 = L }}}
The car will skid 125 feet.