A 400g steel block rotates on a steel table while attached to a 1.20m -long hollow tube. Compressed air fed through the tube and ejected from a nozzle on the back of the block exerts a thrust force of 4.71N perpendicular to the tube. The maximum tension the tube can withstand without breaking is 60.0N . Assume the coefficient of kinetic friction between steel block and steel table is 0.60. (Figure 1)
If the block starts from rest, how many revolutions does it make before the tube breaks?
The Attempt at a Solution
Fbreak = 60 N = mv^2/r → v = sqrt(60r/m) m/s = 180 m/s
a = F/m m/s^2 = 11.775 m/s^2
t = v/a = 15.2866242
s = at^2/2 = 1372.875167
theta = s/r = 1372.875167
revs = theta/(2pi) = 218.499...
Where am I going wrong? I only get a couple of more attempts then the question is locked out..... please help.