- #1
David144
Homework Statement
A flywheel is attached on the output of the gearbox. The output shaft rotates in the opposite direction to the input shaft at 5 times its speed.
The gearbox has an efficiency of 92%. If the flywheel is solid, has a mass of 50kg, a diameter of 1.5m and is to accelerate from rest to 300 revs min-1 in 1min:
a) Calculate the torque required at input T1.
Homework Equations
T=I*α
I=0.5*m*r2
α=I(ω2-ω1)/t
The Attempt at a Solution
Angular velocity of output shaft 300 revs min = 31.41593 rads/s (10π)
Angular velocity of input shaft 60 revs min = 6.283 rads/s (2π)
moment of inertia of flywheel = 0.5*50*0.75^2
=14.0625 Kg m^2
Change in angular momentum =I(ω2-ω1)
=14.0625(10π-2π)
=112π kg m^2 s
Torque = change of angular momentum / time
T=112π/60
=5.86NmI have seen a similar thread but with a completely different method and answer. Any advice please?