- #1

agm1984

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**trouble calculating a projectile's height after a certain distance**

## Homework Statement

A pebble is fired from a slingshot with a velocity of 30.0m/s. If it is fired at an angle of 30deg to the vertical, what height will it reach? If its fall is interrupted by a vertical wall 12m away, where will it hit the wall in relation to the starting position of the pebble in the slingshot?

## Homework Equations

V

_{F}

^{2}= V

_{o}

^{2}+ 2ad

and the 3 other uniform acceleration equations, i guess.

## The Attempt at a Solution

ok, so i used the above equation to solve for d

0=[(30)(cos60)m/s]

^{2}+ (-9.8m/s)d

d = 34.44m ~approx

my trouble comes when i try and calculate how high the pebble will be after 12 meters. if i understand correctly, the question is asking how high up the wall will the pebble hit if it is 12 meters away.

regardless, i am having difficulty creating an equation to solve for that.

it may be interesting to note that i don't know whether the ball will have passed 12m by the time it goes 34m up; however, i assume it will be beyond 12m horizontally, so the ball will still be going up when it hits the wall at 12m.

i greatly appreciate any help.

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