# Homework Help: Projectile Motion, with only Displacement and Angle Known.

1. May 5, 2009

### n72.75

1. The problem statement, all variables and given/known data
A projectile is fired at an angle of 35° and lands 88.5 Meters Down Range.
Assume no air resistance, and a gravatational acceleration of 9.80665 M/S2

I can get as far as the trig, but it doesn't seem like there is enough information to find time or velocity.

Find Initial Velocity Of the Projectile.

2. Relevant equations
a = $$\frac{(V f - V i) }{ t }$$
s = V i + $$\frac{1}{2}$$ at 2

3. The attempt at a solution

See Attachment.

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• ###### Projectile Problem.pdf
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Last edited: May 5, 2009
2. May 5, 2009

### Melawrghk

Break up the motion into x&y components.

Since you know the distance, you can write an equation linking Vi and T (total time). Similarly because horizontal speed doesn't change, you can write an equation linking Vi and N=T/2.

Now, what happens when projectile is halfway there (with respect to the y-component of speed)?

Last edited: May 5, 2009