How to calculate the height of something by throwing an object off it?

by Bellabob
Tags: height, object, throwing
 P: 3 I go rock climbing a lot with my BSA troop, and my friends and I can only estimate the height. I want to know the exact height. Considering I do not have a ruler long enough to measure the height of the cliff, I know there is a way to throw an object off the cliff (say, a rock), time how long it takes to hit the ground, and then do some math and then you have the height. I want to know how to do the math. Please be detailed with your answer, because I'm 15 and not really a math genius (I'm good, but not THAT good). Thanks.
Mentor
P: 21,295
 Quote by Bellabob I go rock climbing a lot with my BSA troop, and my friends and I can only estimate the height. I want to know the exact height. Considering I do not have a ruler long enough to measure the height of the cliff, I know there is a way to throw an object off the cliff (say, a rock), time how long it takes to hit the ground, and then do some math and then you have the height. I want to know how to do the math. Please be detailed with your answer, because I'm 15 and not really a math genius (I'm good, but not THAT good). Thanks.
h = 16t2
t is in seconds and h is in feet.
 P: 1,302 Make sure if you use mark's equation that the rock is either dropped or thrown straight ahead.
 P: 15,319 How to calculate the height of something by throwing an object off it? BTW, there are other ways that might have less error than estimating a time of a second or two. You can figure out how far you are from the base of the cliff and use trig to calculate its height.