A 75 horsepower outboard motor at full throttle will rotate its propeller at exactly 4800 revolutions per min. Find the angular speed of the propeller in radians per second.

Answer 1

the angular velocity = 4800 rev/min * ( 2 π / 60) = 503 rad /s or do the following steps:

Convert rev /min to rev /s, then(4800 rev/min)( min/ 60 s) = 80 rev / s

Every revolution is equal to 2 π rad , then the angular velocity = 80 rev /s * ( 2 π rad / rev) = 503 rad /s

Every HP is equal to 550 lb-ft / s , the torque = T =(75 HP * 550 lb-ft /s / HP ) / ( 503 rad/s) = 82 lb-ft