VIDEO TRANSCRIPT

A stone takes three and a quarter seconds to fall from the top of a cliff. We’ll assume that’s its initial speed is zero meters per second because it was dropped and its acceleration is nine point eight meters per second squared and we’ll choose down to be the positive direction. The formula we’ll use is the distance it’s going to cover, the height of the cliff is: initial speed times time plus one half ‘a’ times‘t’ squared, this first term will be zero because there’s no initial velocity meaning that ‘h’ is: one half times nine point eight meters per second squared times three and a quarter seconds all squared which gives a cliff height of fifty one point eight meters. So the next time you’re out hiking you can drop a stone off a cliff and time its length of descent and square your time and multiply it by five approximately and you’ll have an estimate of your height. For the 5th Edition the stone takes three and a half seconds and the cliff height is sixty point zero meters.