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zmike
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Homework Statement
There is an object glued on a plate that rapidly accerlates upwards (then stops) and then accelerates downwards. Graph the y-component of the normal force on a force vs. time graph. There is an interval of time on the graph inwhich the normal force is negative. How can this be? What does it mean physically for normal force to be negative.
The Attempt at a Solution
Since normal force is caused by electrostatic interactions between molecules, it can only occur perpendicular and AWAY from a surface. It would be impossible for normal force to be negative in this instance but yet my TA says that the question is correct...??
How could normal force be in the same direction as gravity?? Am I missing something important or did I make a mistake somewhere is my understanding?
Please help, thanks in advance