Respuesta :
Answer:
(a). The kinetic energy stored in the fly wheel is 46.88 MJ.
(b). The time is 1.163 hours.
Explanation:
Given that,
Radius = 1.50 m
Mass = 475 kg
Power [tex]P= 15.0 hp = 15.0\times746=11190 watt[/tex]
Rotational speed = 4000 rev/min
We need to calculate the moment of inertia
Using formula of moment of inertia
[tex]I=\dfrac{1}{2}mr^2[/tex]
Put the value into the formula
[tex]I=\dfrac{1}{2}\times475\times(1.50)^2[/tex]
[tex]I=534.375\ kg m^2[/tex]
(a). We need to calculate the kinetic energy stored in the fly wheel
Using formula of K.E
[tex]K.E=\dfrac{1}{2}I\omega^2[/tex]
Put the value into the formula
[tex]K.E = \dfrac{1}{2}\times534.375\times(4000\times\dfrac{2\pi}{60})^2[/tex]
[tex]K.E=46880620.9\ J[/tex]
[tex]K.E =46.88\times10^{6}\ J[/tex]
[tex]K.E =46.88\ MJ[/tex]
(b). We need to calculate the length of time the car could run before the flywheel would have to be brought backup to speed
Using formula of time
[tex]t=\dfrac{46.88\times10^{6}}{11190}[/tex]
[tex]t=4189.45\ sec[/tex]
[tex]t=1.163\ hours [/tex]
Hence, (a). The kinetic energy stored in the fly wheel is 46.88 MJ.
(b). The time is 1.163 hours.
