A propeller is modeled as five identical uniform rods extending radially from its axis. The
length and mass of each rod are 0.823 m and 2.57 kg, respectively. When the propellor rotates at
587 rpm (revolutions per minute), what is its rotational kinetic energy?
Solution
TOTAL MOMENT OF INERTIA=5*ML^2/3 = 5 * (1/3) * 2.57 * 0.823 ^2 = 2.90
kg m^2 ANGULAR SPEED = 587 rpm =587*2*3.14/60=61.43 rad/s KINETIC ENERGY =
0.5* I * w^2 = .5*2.9*61.43^2=5471.78J
length and mass of each rod are 0.823 m and 2.57 kg, respectively. When the propellor rotates at
587 rpm (revolutions per minute), what is its rotational kinetic energy?
Solution
TOTAL MOMENT OF INERTIA=5*ML^2/3 = 5 * (1/3) * 2.57 * 0.823 ^2 = 2.90
kg m^2 ANGULAR SPEED = 587 rpm =587*2*3.14/60=61.43 rad/s KINETIC ENERGY =
0.5* I * w^2 = .5*2.9*61.43^2=5471.78J
