# Physics

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**HELP ME!**
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A pinball machine uses a spring that is compressed 4.0 cm to launch a ball. If the spring constant is 13 N/m, what is the force on the ball at the moment the spring is released?

I don't understand this I guess...

Does the ball leave the spring at the equalbarium position four cm from compression or does it travel past equalbarium and then the ball leaves? Also do I need to know the mass which I know how to do?

Could you please show me how to do this problem and the formulas to use... Thanks for the help