How Accurate Are My Initial Velocity and Maximum Height Calculations?

AI Thread Summary
The calculations for initial velocity and maximum height of a ball thrown upward are incorrect. For initial velocity, the correct formula involves using final velocity, acceleration, and time, rather than a displacement formula. The maximum height calculation also needs to include the initial velocity multiplied by time, which was omitted. Additionally, the calculation for velocity after 1.15 seconds mistakenly used a displacement formula instead of a velocity formula. Overall, the approach needs to be adjusted to apply the correct physics equations for accurate results.
bwilhelm
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Am I anywhere near correct?


Homework Statement


A ball is thrown and upward and reaches it's maximum height in 1.80 sec.

A. Find Initial Velocity
B. Find Max Height Reaced
C. Find Velocity 1.15 sec after being thrown.


Homework Equations





The Attempt at a Solution


A. .5(-9.8)*1.8^2= -15.87 m/sec
B. -15.87+.5(-9.8)*1.8^2 = 31.74m
C. .5(-9.8)1.15^2= -6.48 m/sec
 
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No, not near correct. For part a, you used a displacement formula... so the result won't be a velocity...

Hint: for part a) use the fact that v2 = v1 + at. You know v2, a and t... use those to calculate v1.

For part b) you made a mistake with the formula... it should be s = v1*t + 1/2 at^2... you didn't multiply v1 by t... and also the v1 is wrong since part a was wrong...

For part c)... here again you use a displacement formula... so the result that comes out will be displacement not a velocity... 1/2 at^2 is a distance not a velocity.
 
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