# Projectiles launched at an angle not sure if i posted this already?

## Homework Statement

A diver pushes off horizontally from a cliff 35 m above the water, and they must clear rocks that extend 5 m from the base of the cliff. (a)What minimum pushoff speed is necessary to clear the rocks? (b)How long are they in the air?

## Homework Equations

for (b) t=square root of 35/4.9=2.67 s I understand how to derive the time equation.
for (b) y=v(y direction)t+1/2at^2 x=v(x direction)t

## The Attempt at a Solution

I solved time already, and I got 1.85 m/s for the initial velocity in the x direction, but I cant get the correct initial velocity in the y direction. Im not even sure what Im doing wrong but its frustrating.

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thats actually not projectiles launched at an angle its horizontal projectile motion sorry-I was looking at an angled problem also, which I could use help with too.

hage567
Homework Helper

## Homework Statement

A diver pushes off horizontally from a cliff 35 m above the water, and they must clear rocks that extend 5 m from the base of the cliff. (a)What minimum pushoff speed is necessary to clear the rocks? (b)How long are they in the air?

## Homework Equations

for (b) t=square root of 35/4.9=2.67 s I understand how to derive the time equation.
for (b) y=v(y direction)t+1/2at^2 x=v(x direction)t

## The Attempt at a Solution

I solved time already, and I got 1.85 m/s for the initial velocity in the x direction, but I cant get the correct initial velocity in the y direction. Im not even sure what Im doing wrong but its frustrating.
The initial y velocity is "given" in the problem. It is zero, since he pushes off horizontally.

Oh ok, so I dont even have to solve for that. So the answer is really the initial velocity in the x direction? 1.85 m/s?

hage567
Homework Helper
Yes.

Ok thanks!