How is this gravity question wrong?

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Homework Help Overview

The problem involves a baseball being thrown horizontally towards home plate, with the objective of determining how far the ball drops due to gravity by the time it reaches the plate. The context is within kinematics, specifically focusing on projectile motion and the effects of gravity.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the conversion of speed from miles per hour to meters per second and the calculation of time taken for the ball to reach home plate. There are attempts to apply kinematic equations to find the vertical displacement due to gravity. Questions arise regarding the correctness of units and the reasoning behind the calculations.

Discussion Status

Some participants are providing guidance on using kinematic equations, while others are questioning the original poster's calculations and thought process. There is an ongoing exploration of the problem without a clear consensus on the correct approach or solution.

Contextual Notes

Participants note the importance of units in calculations and the need for clarity in the original poster's reasoning. There is an indication of frustration from the original poster regarding the correctness of their attempts, highlighting potential misunderstandings in the application of the kinematic equations.

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Homework Statement



While trying out for the position of pitcher on your high school baseball team, you throw a fastball at 86.0 mi/h toward home plate, which is 18.4 m away. How far does the ball drop due to effects of gravity by the time it reaches home plate? (Ignore any effects due to air resistance and assume you throw the ball horizontally.)
____m

Homework Equations





The Attempt at a Solution


86 miles per hour = 38.44544 meters/second
18.4 meters / 38.44544 meters.second =0.4786 seconds
0.4786 seconds x 9.81 = 4.695 meters
 
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What are your units on the last equation? That should immediately tell you you are wrong.

Use your kinematic equations for an object in freefall.

\[<br /> y = y_0 + v_{0y} t + \frac{1}{2}at^2
 
Ok I did:

y=0+38.445(0.478)+1/2(9.81)(0.478)^2
It said my answer was wrong.

Then I did 0+0+1/2(9.81)(0.478)^2
Still said it was wrong.

:(
 
And it said that answer was wrong, my last available attempt :(
 
1] What answer did you get? How are we suppsoed to help you if you don't tell us what you're done?


2] Forget the numbers. How are you thinking through this problem?
 

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