hi I have been having trouble with a question and i think i've finally done it. I was wondering if there is anyone that can confirm that i've done this correct.
Here is the question:
Question 3
A flywheel has a mass of 700 kg and a radius of gyration, k of 0.7 m. What is the torque required to increase the speed of the flywheel at a constant rate from 80 rev min-1 to 200 rev min-1 in a time of 20 s? Note that the moment of inertia of a body about an axis = mass*k2 where k is the radius of gyration of the body about that axis.
Mass =700 Kg
k = 0.7 m
Current rev min-1 = 80 rev min-1
Required rev min-1 in 20 seconds = 200 rev min-1
(〖revs〗^(-1)*2π)/60= 〖rads〗^(-1)
The total kinetic energy is given by the formula:
Where:
KE = kinetic energy in J
m = mass in kg
k = radius of gyration in m
ωi = initial acceleration in rad/sec
ωf = final acceleration in rad/sec
= 63191 J
Where:
P = power in W
E = energy in J
t = time in s
The power developed, P = T. Therefore
T=p/ω ω = 2π (RPM/60) 2π(200-80/60)= 12.6 3159.6/12.6= 250.7 Nm
so
Torque Required is 250.7 Nm
Torque Required
Re: Torque Required
