## Catapult

A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H = 33.0 m above sea level, directed at an angle theta = 45.9° above the horizontal, and with a speed v = 28.2 m/s.

Assuming that air friction can be neglected, calculate the horizontal distance D traveled by the projectile.

Assuming that air friction can be neglected, calculate the horizontal distance D traveled by the projectile.

**1.06×102 m**## Discussion

*Anonymous 1*(Thu Jan 21 07:48:22 pm 2010 (EST))

How do we do this problem? HELP Please

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*Anonymous 1*(Sat Jan 23 01:28:15 pm 2010 (EST))

Can anyone please help me on this one!!!

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Hi, I am having a real hard time trying to figure this out. I've done the quradratic

equation and I figured out the plus and minus results, but I don't know what to

do next!

Can anyone help me... PLEASE!!!!!!

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**Re: Please HELP!!!!**

*Anonymous 3*(Sat Jan 23 09:36:44 pm 2010 (EST))

Here's what I did.

First I used the equation y=yo+vo*(sin theta)*t + .5gt^2

Everything you need will be there except for time. Rearrange

that such that you'll have an equation that can be solved

using the quadratic equation (there's that again), and use

the bigger value of t for time.

Plug that into x = vo* (cos theta)* t , which you just

found, and there you have it.

Just to clarify, yo is the initial height, and vo is the

initial velocity.

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Right now I just cannot understand why I'm not getting this right...I got 3.555

and .1225 for the time and when I plug it into that equation I have got 3 wrong

answers....can anyone tell me if my time's are right and why I'm not getting this.

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*Anonymous 5*(Sun Jan 24 02:55:03 pm 2010 (EST))

make sure that you have g as a negative value.. thats why your time values are

wrong... you should get only one positive answer out of the quadratic equation

and use that value to plug into the equation he explained above...

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**A little more help please**

*Anonymous 6*(Sun Jan 24 05:39:19 pm 2010 (EST))

Am I using the correct A,B,and C for the quadratic equation?

A=Height(35.0)

B=Vo(30.8)

C=sin(theta)(47.3deg)

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Thank you so much, I got it!!! :D