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

this means that the temperature of both substances will be equal

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.