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

Suppose you were asked to find the torque about point p due to the normal force n in terms of given quantities. which method of finding the torque would be the easiest to use?

How have the competing explanations' experiments on atoms affected the development of the atomic model?

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct