A futuristic design for a car is to have a large disklike flywheel within the car storing kinetic energy. The flywheel has mass 370 kg with a radius of 0.50 m and can rotate up to 540 rev/s. Assuming all of this stored kinetic energy could be transferred to the linear velocity of the 1600 kg car, find the maximum attainable speed of the car.

Explanation:

Rotational kinetic energy of flywheel

= 1/2 Iω² where I is moment of inertia , ω is angular velocity

for wheel I = 1/2 m R² where m is mass and R is radius of flywheel

Putting the values

I = 1/2 x 370 x .5²

= 46.25 kg m²

ω = 2πn where n is frequency of revolution per second

ω = 2 x 3.14 x 540 = 3391.2

Rotational kinetic energy = .5 x 46.25 x 3391.2²

= 265.94 x 10⁶ J

If this energy is transferred to a car of mass 1600kg , velocity acquired by it be v , then

kinetic energy of car = rotational kinetic energy of flywheel

= 1/2 m v ² =  265.94 x 10⁶

.5 x 1600 v² = 265.94 x 10⁶

v² = 33.24 x 10⁴

v = 5.76 x 10²

= 576 m /s

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees. 

probably not if net force is zero