Projectile motion - Finding velocity (not given time or angle)

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SUMMARY

The discussion centers on calculating the initial velocity of a baseball hit to reach a maximum height of 20.0 meters and travel a horizontal distance of 90.0 meters. Participants emphasize the importance of using the relationships between distance, speed, and angle to derive the necessary equations. The key takeaway is that two equations can be formed: one from the maximum height and another from the total distance traveled, which can be solved simultaneously to find the initial velocity. The user successfully solved the problem after clarifying these relationships.

PREREQUISITES
  • Understanding of projectile motion principles
  • Familiarity with kinematic equations
  • Knowledge of trigonometric relationships in physics
  • Ability to manipulate algebraic equations
NEXT STEPS
  • Study the kinematic equations for projectile motion
  • Learn how to derive equations for maximum height and range
  • Explore trigonometric functions related to angles in projectile motion
  • Practice solving problems involving initial velocity and trajectory
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Students studying physics, educators teaching projectile motion concepts, and anyone looking to improve their problem-solving skills in kinematics.

vbillej
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Homework Statement



A baseball is hit so that it reaches a maximum height of 20.0m and travels 90.0m before hitting the ground. With what velocity is the ball hit?

The Attempt at a Solution



I'm confused, i went into trying to find the time but i couldn't without a given angle. I went to say that 20.0 is the peak so time to the peak would double for the total time but couldn't get time.

This also blocked me to find the initial velocity of y and x.
need help please.
 
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vbillej said:

I went to say that 20.0 is the peak so time to the peak would double for the total time but couldn't get time.


Fine, you were on the right track.

I ask you two questions - what are the expressions for greatest distance and highest distance?

You have been given two pieces of data, right? Make an equation, man!

Distance traveled is 90 m. From this piece, you can get a relation between speed and angle.

Also, from the peak being 20 m above, you can get another relation between speed and angle.

That'd be enough, actually!
 
yea got the equation now, solved it in the shower haha. Thanks for the reply
 

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