Question

A car is designed to get its energy from a rotating

Answer 1

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 $P= 15.0 hp = 15.0\times746=11190 watt$

Rotational speed = 4000 rev/min

We need to calculate the moment of inertia

Using formula of moment of inertia

$I=\dfrac{1}{2}mr^2$

Put the value into the formula

$I=\dfrac{1}{2}\times475\times(1.50)^2$

$I=534.375\ kg m^2$

(a). We need to calculate the kinetic energy stored in  the fly wheel

Using formula of K.E

$K.E=\dfrac{1}{2}I\omega^2$

Put the value into the formula

$K.E = \dfrac{1}{2}\times534.375\times(4000\times\dfrac{2\pi}{60})^2$

$K.E=46880620.9\ J$

$K.E =46.88\times10^{6}\ J$

$K.E =46.88\ MJ$

(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

$t=\dfrac{46.88\times10^{6}}{11190}$

$t=4189.45\ sec$

$t=1.163\ hours$

Hence, (a). The kinetic energy stored in  the fly wheel is 46.88 MJ.

(b). The time is 1.163 hours.