you look up and see a helicopter pass directly overhead. 3.10s later you hear the sound of the engine. if the air temperature is 23.0 degrees c, how high was the helicopter flying?

What is the final velocity of the initial velocity of 25 and -50?

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

What is the role of lenses in microscopy?