How do i work out the mass of a flywheel. I am given the density as 7500kg/m3, a 500mm diameter and a 10cm thickness.
Please help
Switch to the same units, metres.
- good thing we are in metric
diameter = 500 mm = 50 cm = .5 m
so radius = .25 m
height = 10 cm = .1 m
volume of flywheel = π r^2 h
= π(.25)^2 (.1) = .00625π m^3
mass = 750(.00625π) kg
= appr 147.26 kg
Many thanks Reiny
To calculate the mass of a flywheel, you need to use the following formula:
Mass = Density × Volume
To find the volume of the flywheel, you first need to calculate the volume of a cylinder, since a flywheel can be approximated as a cylinder.
The formula for the volume of a cylinder is:
Volume = π × (radius)² × height
Given that the diameter of the flywheel is 500mm, you can find the radius by dividing the diameter by 2:
Radius = Diameter / 2
In this case, the diameter is 500mm, so the radius is 250mm.
However, it is important to convert the radius to meters because the density is given in kg/m³. So, divide the radius by 1000 to convert it to meters:
Radius = 250mm / 1000 = 0.25m
The thickness of the flywheel is given as 10cm, which is equivalent to 0.1m.
Now, you have all the necessary measurements to calculate the volume:
Volume = π × (0.25m)² × 0.1m
You can use the value of π as approximately 3.14.
Volume = 3.14 × (0.25m)² × 0.1m
= 0.019625m³
Finally, you can calculate the mass using the given density:
Mass = 7500kg/m³ × 0.019625m³
= 147.1875kg
Therefore, the mass of the flywheel is approximately 147.1875kg.