Oboesmrtguy40

3. [SF6 1.P.035.]
A point is located in a polar coordinate system by the coordinates r = 2.0 m and = 35°. Find the x and y coordinates of this point, assuming the two coordinate systems have the same origin.

For my X coordinate I got 2, which it is telling me is wrong
For my y cooridinate I got 1.12, which it is telling me is correct

I did:

x= r cos of theta = 2cos(35)= -1.80738
y= r sin of theta = 2 sin(35)= -.856368

r = square root of (X^2 + y^2)
r= square root of apprx. 4
so r = 2, so why is my x coordinate wrong? r IS the x coordinate. what did I do wrong.

Next Problem is:
An automobile tire is rated to last for 55 000 miles. Estimate the number of revolutions the tire will make in its lifetime.

How am I supposed to find that if I dont know the speed or the diameter??

lil_killer129

You Are In Radians!

budgiekid90

And for the second one, it's estimate--estimate circumference, then convert miles to whatever you used and divide for revs. Yeah, those estimate questions are rather irritating, but seem to be the first chapter of every physics book.