physics
posted by Anonymous .
a straight road is inclined 30 degees to the horizontal and a man is walking along the road at the rate of 2 and a half miles an hour. how many feet does he ascend vertically against the force of gravity in 15 minutes?

sin30 = 0.5
That means that for every mile traveled on the road (hypotenuse), he rises .5 miles in elevation (opposite side).
So, since 15 min = .25 hr, he has traveled 2.5 * .25 = .625 miles, and gained .3125 miles = 1650 ft in elevation.
That's some steep grade: 50%! 
thanks steve! :)