Calculating Work Done by a Pitcher: Physics Homework [SOLVED]

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The discussion focuses on calculating the work done by a pitcher when throwing a baseball. The baseball's initial speed is 32.5 m/s, and its mass is 0.145 kg, with air resistance ignored. The correct formula for kinetic energy is identified as K = 1/2 mv^2, leading to the calculation of work done as W = K2 - K1. After correcting the initial calculations, the total work done by the pitcher is determined to be approximately 76.58 joules. The thread concludes with a clear solution to the physics problem.
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[SOLVED] Work Done by Pitcher

Homework Statement



A baseball leaves a pitcher's hand at a speed of 32.5 m/s. The mass of the baseball is 0.145 kg. You can ignore air resistance.

How much work has the pitcher done on the ball by throwing it?

The Attempt at a Solution



velocity initial = 32.5
velocity final = 0 (it has to stop eventually right?)
mass of ball = .145

K = mv^2

K1 = (.145)(32.5)^2 = 153.16
K2 = (.145)(0)^2 = 0

Wtotal = K2-K1

Wtotal = 0 - 153.16

:confused:

Solution: 76.6 J
 
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Heat said:
How much work has the pitcher done on the ball by throwing it?
They are talking about the work done by the pitcher in taking a ball from rest to its top speed as it leaves his hand.

K = mv^2
That's not quite right.
 
haha,

I forgot it was

K = 1/2mv^2

ok, now that I got 76.58.

ah, I see now.

so it's this then

K2 = .5(.145)(32.5)^2 = 153.16
K1 = .5(.145)(0)^2 = 0

Wtot = K2-K1 = 76.58
 

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