Mechanics problem

vendredi 1 août 2014

1. The problem



A 3 kg object is moving in a plane with its x and y coordinates given by x = 5t^2 -1 and y = 3t^3 +2 where x and y are in meters and t is in seconds. Find the magnitude of the new force acting on this object at t= 2s



2. My attempt.



So my first attempt is to find a vector expression for acceleration. I integrated the expressions for x and y to give



V subx = 5/3 t^3 -t +c



To find the constant on integration I found the position of the particle at t=0 and t=2. Therefore calculating the velocity at 2 seconds. Thus the constant of integration for this expression is -4/3



The velocity at 2s being 10i+12j ms^-1



I have done the exact same process for velocity in the y direction and reached an expression for Vsuby .



My problem is I'm not sure how to get a valid expression for acceleration, and this seems like a really long winded way of answering this question.





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