Third Law of Motion Problem Finding average Force

AI Thread Summary
A 9800kg rocket accelerates from 11m/s to 22m/s in 0.75s, prompting a calculation of the average force from the expelled gases. The correct net acceleration is determined to be 14.67m/s², calculated by rearranging the equation for acceleration. The average force is then calculated using F = mass x acceleration, resulting in 143,000N. An initial miscalculation led to confusion, but the error was identified and corrected. The discussion highlights the importance of careful calculation in physics problems.
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1. A 9800kg rocket is traveling east along a horizontal frictionless rail at a velocity of 11m/s. The rocket is then accelerated uniformly to a velocity of 22m/s in a time of 0.75s by the expulsion of hot gases. What is the average force at which the gases are expelled by the rocket?



Homework Equations





3.
Finding the net acceleration.
22 = 11+a(0.75)
18.333=a
Finding force.
F = 9800x18.33
F = 179634

What have I done wrong here?
 
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Welcome to PF, Twisted!
My calculator says 14.67 for that
22 = 11+a(0.75)
11 = .75*a subtracted 11 from both sides
a = 11/.75 = 14.67 divided both sides by .75
 
Ugh, I can't believe I entered it into my calculator wrong. I got it right now. Thanks a lot for the quick response!
 
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