Another Physics Problem

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Ok guys, here's some fun with ballistics in 2-D.

A snowball rolls off a roof that has an angle of 40(degrees) at a speed of 7.00m/s. The height that the snowball falls from is 14.0m. Ignoring air resistance, calculate how far out from the building the snowball travels.

So far I just assumed that Vy was 0 at the groud... Im not sure if this is the right way, but I was able to get a time, and from that I started to calculate how far out the snowball fell.

Looking for some ideas, cause I'm not sure my argument holds water... And if it does, can someone please explain why?

I shouldn't butt in where I know absolutely nothing, but I'm struck by your suggestion that the answer should "hold water" - which is exactly what a snowball does. Is there something about water that should be factored in? I apologize for this, it's way off math, sorry. Couldn't resist, my own favorite topic is Jung.

If you fire the snowball off the roof at a fixed speed horizontal to the ground, it will travel a parabolic path to the ground. The time taken for the fall component is the same whether it has any horizontal speed in the vector.

However this is confused by the fact that there is some horizontal speed and some vertical speed (downwards) and some rotational speed (do we ignore this?) when the snow ball gets to the edge of the roof.

Somehow you have to add the speed the ball has imparted by the roll down the roof - with the speed it gets accelerating to the ground.

I don't think assuming the speed is zero because it hits the ground is helpful. This would be like assuming the snowball is going to slow down over the whole of its fall to gently hover over ground and touch down oh so gently like a snow flake - not smashed to bits like the watermelon.

You really want to know what the speed of the snowball both horizontally and vertically is immediately before it makes contact with the ground, I think you could possibly ignore the decelleration and transfer of energies as it smashes - because this isn't going to be easy to measure in terms of horizontal travel. You could probably safely assume they only want to know how far out the ball is when it *lands* / impacts - and not how far it might roll or bits of it might fly to after that.

lol, sorry about the literal mixup. This is a very simple look at the fall of the snowball, we are not accounting for rotational speeds, or even mass. We are simply looking for the time that it takes for the snowball to fall 14.0m. If you guys have any ideas, let me know, I can pretty much take it from there.

from that formulae page...

http://www.krysstal.com/formulas.html

g =9.8m/s/s
height = 1/2 * (g * tfall * tfall)

re- arrange to work out time for fall (tfall)

so height = 14m

tfall * tfall = (height * 2 ) / g

tfall = Square root of ( (height * 2 ) / g )

t = time to fall.

Now you just need to work out how far sideways it will go in that time with its speed vector (don't forget need to take something off or add it somewhere else for the downward component)

Ie the downward speed component should maybe make the time for the fall shorter. I guess it effectively reduces the height? Then you use the new height - fall to work out the new time, and consequent parabola?

speed = distance / time
we know speed and time (sort of), so rearrange...
that would give you a very approximate answer discounting lots of stuff that is probably important. I hate when Physics does that....

Warning, problem solution: