This is a tedious problem.
Luckily there are web resources
BE SURE to click "show steps"
You can change the question to .
That will help you find the second derivative or
The position vector of a point is given by . Prove that:
a)
b) the angle between the position vector and the acceleration vector is constant. Calculate this angle.
Answer: b) pi/2
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I tried to derive the position vector two times but it isn't working.
This is a tedious problem.
Luckily there are web resources
BE SURE to click "show steps"
You can change the question to .
That will help you find the second derivative or
For the second question you can calculate the scalar product of the vectors like:
The scalar produt will tell you more about the angle between the vectors, but first you've to determine the coordinates of the vector r(t) (see Plato's post).
Yes the dot product, see reply #3.
You should explore what all wolframalpha will do.
Look at this.