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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: Andiio on November 04, 2011, 07:44:10 pm

Title: Initial conditions Q
Post by: Andiio on November 04, 2011, 07:44:10 pm

Attached is the Q!

My reasoning to take the positive sq root of the velocity was that:
At t = 0, v = 1/2 m/s, and a = 3 m/s^2 which is >0, so at t=0, the body of mass is accelerating from 1/2 m/s and so must be positive.



However, in the solutions the reasoning was that 0<v<1.

Would I still be able to gain full marks for my reasoning?

Title: Re: Initial conditions Q
Post by: dc302 on November 04, 2011, 08:36:11 pm

Yes you would get full marks for that also, noting that a positive square root is strictly positive and a neg root is strictly negative, so if you took the negative root, there would have been no way for the velocity to be positive 1/2.