- #1
MarcZZ
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Homework Statement
It takes 139 kJ of work to accelerate a car from 22.8 m/s to 27.7 m/s. What is the car's mass?
Homework Equations
Well, we know that work is also known as J and J is = to kg*m^2/s^2 so we can use the equation J = m(vf - vi) to solve this I think.
The Attempt at a Solution
So We know that 139 kJ is equal to 139x10^3 J. Also m(27.7 m/s - 22.8 m/s) = m(4.9m/s), so combing these we assume that 139000 J = ?kg(4.9m/s) But from here I'm getting confused badly. I think I'm misusing the equation somehow as I'm not sure how to manipulate the 4.9m/s in order to get rid of the kg*m^2/s^2 units on the other side.
Any help will be much appreciated. :)