Amodel of a helicopter rotor has four blades, each of length 3.30 m from the central shaft to the blade tip. the model is rotated in a wind tunnel at a rotational speed of 510 rev/min . what is the speed of the blade tip

This motion of helicopter rotor blade is an example of circular motion.

We have the angular velocity of rotor blade = 510 rev/min

                                                                         = (510*2)/60

                                                                          = 53.41 rad/s

We have the linear velocity of circular motion = radius * angular velocity

So the  speed of the blade tip of helicopter = 53.41 * 3.30

                                                                         = 176.24 m/s

Speed of the blade tip of helicopter = 176.24 m/s

b.a device that inputs heat into a cool object