Word problem?

Question

The distance (d) a ball will roll down an inclined plane is directly proportional to the square of time (t). If the ball rolls 20 inches in 2 seconds, how far will it roll in 5 seconds?

I kind of got stuck on this problem. I don't like word problems at all. Can some one please explain to me, how to do this problem!

Thanks a lot

Answer 1

directly proportional to the time squared means
d = k*(t^2) where k is some constant we have to figure out.
So we know 20 = k * (2^2) or 20 = k*4 so k = 5.
For 5 seconds, we have d = 5*(5^2) = 5*25 = 125 inches

Answer 2

Distance proportional to time squared means...

D = c T^2 where c is a constant.

20 = c * 2^2 = 4c so c = 5

D = 5 * 5^2 = 5 * 25 = 125 inches.

Answer 3

directly proportional to the square of time means that if you double the time (from 2 to 4 seconds) you will square the distance (from 20 to 400 inches). The answer will be more than 400 inches.

Hope that is enough of a hint.