Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel’s energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5m diameter and a mass of 260kg . Its maximum angular velocity is 1500rpm .
i know that torque equals to P/omega but Ive already tried so many times .
so like
A motor spins up the flywheel with a constant torque of 57Nm . How long does it take the flywheel to reach top speed? t=200s
How much energy is stored in the flywheel? E=9.0×10^5 J
The flywheel is disconnected from the motor and connected to a machine to which it will deliver energy. Half the energy stored in the flywheel is delivered in 2.5s . What is the average power delivered to the machine? P=1.8×10^5 W
how much torque?!?!?!?! give answer in Nm
Ive tried 1146Nm, 1684Nm….
the correct answer was 1300 WHICH I HAD ABSOLUTELY NO IDEA HOWWWW!! 🙁
1 Answer

Your calcs all look OK.
1500rpm = 1500*2pi/60 rad/s = 157 rad/s
So the torque should be T = P/w = 1.8*10^5 / 157 Nm = 1150 Nm (3 sig. figs)