A model of a helicopter rotor has four blades, each 3.40 m long f...

Question

A model of a helicopter rotor has four blades, each 3.40 m long from the central shaft to the blade tip. The model is rotated in a wind tunnel at 550 rev/min. (a) What is the linear speed of the blade tip, in m/s?

Accepted Answer

Welcome back, everybody. We have a wind turbine. So let me go ahead and trawl our wind turbine here. And with any good wind turbine, we have the blades cutting out of it. Now, we are told that any given one of these blades has a length of 100 and 20 ft, meaning the circle that this propeller makes has a radius of 100 and ft. We're also told that it rotates with an R PM of 10. We are asked to find what the linear speed is at the blade tips. Well, our linear speed or our tangential velocity is going to be equal to radius times our angular velocity given by omega. So we actually need to convert this value into our Omegas because our omega is given in radiance per minute. We are given 10 revolutions. Sorry, are you here revolutions for one minute. So let me go ahead and multiply this by two high gradients over one revolution. Since we know there are two pi radians and one revolution these units cancel out. And we are given that our angular velocity is 20 pi radiant per in it right now that we have this value, we can go ahead and plug it into our above formula to find our tangential velocity. Our tangential velocity is equal to our radius of 100 and 20 ft times or angular velocity of 20 I. And when you plug this into our calculator, we get that our tangential velocity is 7540 ft per minute corresponding to our final answer. Choice of B Thank you guys so much for watching. I hope this video helped. We will see you all in the next one.

A model of a helicopter rotor has four blades, each 3.40 m long from the central shaft to the blade tip. The model is rotated in a wind tunnel at 550 rev/min. (a) What is the linear speed of the blade tip, in m/s?

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