- anonymous

A rock is dropped from a cliff. How high is the cliff if the rock falls (1/3) of the total height of the cliff in the last second of it's fall?

- jamiebookeater

See more answers at brainly.com

At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your **free** account and access **expert** answers to this

and **thousands** of other questions

- anonymous

2h=gt^2

- anonymous

now distance travelled in the last second (t) is h/3

- anonymous

2h/3= g[(t^2 - (t-1)^2)}

Looking for something else?

Not the answer you are looking for? Search for more explanations.

## More answers

- anonymous

that should do it

- anonymous

got it?

- anonymous

I'm not realy sure where you are getting the {t^2-(t-1)^2} to be honest. I understand 2h=gt^2.....but then it looks like you divided that by 3 and then didn't do the same to the otherside ha......wait...maybe I do see what you did..you constrained t so that however long it takes for rock to fall 2/3 the height, it's always 1 less than the total fall time....but i'm still not sure how this will give me the cliff's height ha

- anonymous

from the first eqn get t, which is is the total time traveled

- anonymous

then the distance in the last second, is the distance in t seconds - distance in t-1 seconds right?

- anonymous

so h/3 = [gt^2 - g(t-1)^2] / 2

- anonymous

so now uve got 2 eqns and two variables t and h

- anonymous

eliminate t from the system of equations and get h

- anonymous

got it?

- anonymous

the answer is around 173 meters

- anonymous

and him, your method is incorrect, btw.

- anonymous

how com?

- anonymous

2h/3= g[(t^2 - (t-1)^2)}
how did you get this?
also, in the last second of its fall, the rock already has an initial velocity. You are discounting that.

- anonymous

tht gets subtracted neway

- anonymous

linalg009, is that the correct answer in your book?

- anonymous

learn to read..i explained it above

- anonymous

I almost feel like I'd have to trial and error it until I get around the correct time for the last second of the fall. ha....It doesn't have an answer in the book :/

- anonymous

oops....I mean get the right distance for the last second of the fall ha....i ration of 1/3

- anonymous

ratio*

- anonymous

so now the qustn is?

- anonymous

The question is...can I just plug in different values for the initial height of the drop until I get around 1 sec. for the last third of the fall ha..somehow

- anonymous

wtdu hav to find out temme clearly

- anonymous

It's the same question. I'm trying to find out the height of the cliff. I was just trying to think of a different method

- anonymous

ive told u the method..wat part do u not get? im positive its correct

- anonymous

What are the two equations? 2h=gt^2 and 2h/3= g[(t^2 - (t-1)^2)}..?

- anonymous

yeah right

- anonymous

t=sqrt(2h/g)

- anonymous

or first u divide the two to make a quadratic eqn in t

- anonymous

then get the value of t and plug it into the first eqn to get h..got it?

- anonymous

ya...solving now ha

- anonymous

yes, him is right. I did not read what he had posted correctly.

- anonymous

the answer is around 145-150 meters.

- anonymous

I get 145.52 meters

- anonymous

yes, thats right.

- anonymous

Perfect! Thanks for the help him1618 and dhatraditya ha..it makes perfect sense now! ha.

Looking for something else?

Not the answer you are looking for? Search for more explanations.