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Plutonium88
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Homework Statement
a planet with radius of 12km spins at 520revs/s
find:
a) avg speed of a point on the planets equator over 2.5 of a revolution
b)find avg acceleration on stars circumfrance over 3/4 of a rev
c)find distance covered by point on the equator in 1 second
d) find displaement
f=520rev/s r=12000m
Homework Equations
fc=mv^2/r
T=1/f
v=2piR/T
The Attempt at a Solution
a) if i construct a vector triangle using v1 and v2 at the beginning of 3/2 of a rev and at the end, i can believe i can solve for vavg this way making a triangle where Vavg opposes the angle of 144 degrees...
v=2piR/T
where T=1/f
so i get v=2Pi*Rf
i considered V1and V2 = vvavg^2 = 2(2Pi*R*f)^2-2(2Pi*R)^2cos144
is this okay?
b)m*ac=mv^2/R
where ac = centripetal accell
and v = 2pi*R*F
ac = ((2pi*R)*f)^2/R
c)m*ac= (d/t)^2/R
if t=1s
d=√(R*ac)
d)... i think i may have solved displacement above.. perhaps i am confusing the distance and displacement.