Max height-2 balls-1 straight up-the other horizontal at an angle? yikes

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SUMMARY

The discussion focuses on a physics problem involving two balls: one thrown vertically and the other at an angle of 67° to the horizontal. The first ball, thrown straight up, returns to the thrower's hand after 4 seconds, indicating a maximum height achieved at 2 seconds. The acceleration due to gravity is given as 9.8 m/s². To find the initial speed required for the second ball to reach the same height, the vertical component of its velocity must equal that of the first ball, which is calculated using the kinematic equations.

PREREQUISITES
  • Understanding of kinematic equations in physics
  • Knowledge of projectile motion concepts
  • Familiarity with trigonometric functions, particularly sine and cosine
  • Basic grasp of gravitational acceleration (9.8 m/s²)
NEXT STEPS
  • Calculate the maximum height of the first ball using the formula H = 0.5 * g * t²
  • Learn how to decompose velocity into horizontal and vertical components using trigonometric functions
  • Explore the use of kinematic equations for projectile motion
  • Investigate the relationship between time of flight and maximum height in projectile motion
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Students studying physics, particularly those focusing on mechanics and projectile motion, as well as educators looking for problem-solving strategies in kinematics.

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Homework Statement


A ball is thrown straight upward and returns
to the thrower’s hand after 4 s in the air. A
second ball is thrown at an angle of 67◦ with
the horizontal.
The acceleration of gravity is 9.8 m/s2 .
At what speed must the second ball be
thrown so that it reaches the same height as
the one thrown vertically? Answer in units of
m/s.


The Attempt at a Solution



*****I've been working on this problem for a few days. Here's what I have so far:

This is a 2-d question. First I need to find the maximum height of the first ball (thrown straight up) then I can plug that into the second ball's equations and find the Vo(x) of the second ball.
**Will the ball that's being thrown straight up have it's maximum height at 2s (half way between the total time?)
So I would have Y=0 + 0(1)+ (+)4.9(1^2).
Then Height would be +4.9? I think that gravity COULD be + because the ball is going up...but I don't know if that even makes sense.

Then I would put the Y into my second ball's equations:
1.) Y EQN: 4.9=0+Vo(y)sin(67)(t)+4.9(t^2)
2.) X EQN: x=0 + Vo(x)cos(67)(t)+ 0
3.) Vy EQN: 0=Vo(y) + -9.8(t)
4.) Vx EQN: Vx=Vo(x) + 0

**Substitute and solve for t: t=.___s
**Plug t into X EQN: x=Vo(x)cos(37)(.__s)
Now I am missing x and the magnitude.

I really don't know what to do with this problem. Any help is greatly appreciated! Thank you! :)
 
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You need to find the initial vertical velocity the first ball has. That will be the same vertical velocity your second ball has.
 

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