Calculate the centripetal acceleration module in the following cases as a multiple of g = 9.8 m / s ^ 2.
a) a car traveling at 100km / h on a curve of radius 50m.
b) a jet plane flying at 1,500 km / h and making a turning radius of 5km.
c) a stone that is rotated every 0.5 s after a string of length 1 m
d) a speck of dust on the edge of a disk of 30 cm diameter rotating at 33.33333 ... rev / min.
e) a molecule in a centrifugal radius of 15cm rotating at 30,000 rev / min.
g= 9.8 m/s2
ar = v2/r
ar = ug
u: coefficient of friction(WHERE DO I GET THIS?!)
haven't touched b) and on yet..
The Attempt at a Solution
so heres how i began...
vi = 100km/h = 10 000m/3600s = 27,78m/s
ar= 1002/50 = 200 m/s2
ar = 9,8u
Okay... so how do i get the coefficient of friction(u) if im not given any mass value?