Velocity under constant acceleration

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Homework Help Overview

The discussion revolves around a problem in projectile motion, specifically calculating the initial velocity required for a puma to reach a certain height when jumping at an angle. The original poster attempts to determine the necessary speed to achieve a jump height of 3.7 m.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants explore the need to break down the velocity into its x and y components, question how to derive these components without an initial velocity, and discuss the correct equations to use for the calculations.

Discussion Status

There is ongoing exploration of the correct approach to find the initial velocity, with some participants offering equations and others verifying calculations. Multiple interpretations of the problem are being discussed, particularly regarding the relationship between the vertical component of velocity and the overall initial velocity.

Contextual Notes

Participants note that the original poster's calculations may have been affected by using the wrong mode on a calculator, and there is mention of confusion regarding which variable to solve for. The discussion also highlights the angle of the jump as a critical factor in the calculations.

nbroyle1
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The best leaper in the animal kingdom is the puma, which can jump to a height of 3.7 m when leaving the ground at an angle of 45°. With what speed must the animal leave the ground to reach that height?

knowns: y=3.7 yo=0 Vo=0 V=want!

I tried finding the velocity by using the equation V^2=0+2(-9.8)(-3.7) but ended up with the wrong answer. What am I doing wrong?
 
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Do I need to get velocitys for the x and y components of the jump?? how do I do that?
 
This is projectile motion, so you have the break the velocity into components.
 
but I am not given a velocity so how do I break it into components?
 
The initial velocity is what you are looking. It's not zero.
the equation you want to use is ymax=((Vo^2)sin^2(theta))/2g
i believe
 
the solution i got is 10m/s if anyone else can verify
 
AmritpalS said:
the solution i got is 10m/s if anyone else can verify
Hmm, I'm obviously having finger trouble because I get nearer 12 m/s.
 
How do you know what the Vo is though?
 
yes the answer was 12m/s
 
  • #10
The equation in the first post gives only the vertical component of velocity, you want the initial velocity.
 
  • #11
sorry about that i plugged it into my calculator on radian mode. Should have just done it in my head. It is 12m/s sorry about that i guys
 
  • #12
NemoReally said:
Hmm, I'm obviously having finger trouble because I get nearer 12 m/s.
no finger trouble is on me
 
  • #13
nbroyle1 said:
How do you know what the Vo is though?
What you calculated in your original message was the vertical component of the puma's velocity.

The problem states that the puma's jumped at 45 deg from the horizontal and, as AmritpalS stated, you then need to work out what this works out as given the vertical component ... look at AmritpalS's equation and re-arrange it.
 
  • #14
Ok thanks yea I was just trying to solve for the wrong variable. That equation is a little new to me Ill have to remember that one.
 

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