The rotating blades of a hovering helicopter sweep out an area of radius 4m imparting a downward velocity of 12m/s to the air displaced. A) find the mass of the helicopter.
B) the speed of rotation of the blades of the helicopter is increased so that the air now has a downward velocity of 13m/s. find the upward acceleration of the helicopter

Which statement best describes who the period and frequency of electromagnetic was change between gamma rays and microwaves? a) the period and frequency stay the same. b) the period increases and the frequency decreases. c) the period decreases and the frequency increases. d) the period increases and the frequency increases.

Afigure skater is rotating at a rate of 200 revolutions per minute. what is the angular speed, in units of rad/s? 20.9 12000 200 3.33

Wo small variable-thrust jets are actuated to keep the spacecraft angular velocity about the z-axis constant at ? 0 = 1.16 rad/s as the two telescoping booms are extended from r1 = 1.18 m to r2 = 4.69 m at a constant rate over a period of 124 seconds. the small 19-kg experiment modules at the ends of the booms may be treated as particles, and the mass of the rigid booms is negligible. determine the necessary thrust t for each jet as a function of time where t = 0 is the time when the telescoping action is begun. after you have the general expression for t, answer the questions. show work.