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# Mechanics (motion) qestion watch

1. Hi guys,
I hae a question which I am struggling on.

A particle of mass m moves under the action of a resistance of magnitude mkv^2 and a restoring force of magnitude mAk towards the origin x = 0

Write down the equation of motion in the cases

a) x > 0 and v > 0
b) x > 0 and v < 0
c) x < 0 and v < 0

Thanks
2. You need to work out what the forces are and what direction they act in.

Hint:

A resistive force acts in the opposite direction to the velocity.

A restorative force acts in the opposite direction the the displacement (from the origin).
3. for a) I have d^2x/dt^2 = Ak - kv^2
for b) i have d^2x/dt^2 = Ak + kv^2

I am not sure about c)
4. Which direction does the 'Ak' force go in?
5. (Original post by DFranklin)
Which direction does the 'Ak' force go in?
The information above is all that is given to me.

I know I am right for a) and b) but I cannot get c). Is there anyone out there who can help?
6. (Original post by DFranklin)
Which direction does the 'Ak' force go in?
It says towards the origin x = 0

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