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

  • Thread starter aly1201
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  • #1
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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.
 

Answers and Replies

  • #2
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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.
 
  • #3
hage567
Homework Helper
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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.
 
  • #4
11
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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?
 
  • #5
hage567
Homework Helper
1,509
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Yes.
 
  • #6
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Ok thanks!
 

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