A skydiver jumps out of an airplane. After 0.8 seconds, she has fallen 100 feet. How far will she fall after 15 seconds?

Question

this  is a 'proportion question

Answer 1

Okay, even if it is unrealistic, you can solve it.  Set up two fractions equal to each other.  .8/100 = 15/x.  Basically you are saying, ".8 seconds is to 100 feet as 15 seconds is to x feet."  Then you cross-multiply.  .8x = 1500.  Finally, to find x, you divide both sides by .9.  On the left .8/.8 equals 1, so you just have x.  On the left, 1500/.8 = 1875.  So, in 15 seconds she will fall 1875 feet.

Answer 2

0.8/100 = 15/f

 

Cross multiply.

 

0.8f = 1500

 

I bet you can solve for f from here.

 

No, this technically isn't accurate as far as acceleration works, but you'll learn about that later.