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View Full Version : Angular Velocity Question????


scott.leever
Oct24-07, 09:46 AM
In March 2004, a British company successfully tested a power system to tap the energy of ocean tides. The energy will be stored in an underwater turbine consisting of two metal blades, each 15.0 m long. The movement of the water due to the tides will give kinetic energy to the turbine blades, causing them to spin. In the calculations that follow, ignore any frictional drag due to the seawater.

If we model each of these two blades as a thin uniform steel bar 15.0 m long and 25.0 cm in diameter, at what rate rad/s and rpm must they spin for the turbine to store 1.00 MJ of energy? The density of steel is 7800 kg/m^3 . (Recall that density is equal to an object's mass divided by its volume.)

How do i solve this?? THANKS!

Astronuc
Oct24-07, 11:54 AM
Here are some equations of motion for both linear and rotational motion
http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

Moments of inertia for common geometries.
http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html#cmi

Rotational kinetic energy
http://hyperphysics.phy-astr.gsu.edu/hbase/rke.html#rke

Select the appropriate geometry.