Starting from rest, your friend dives from a high cliff into a deep lake below, yelling in excitement at the thrill of free-fall on her way down. You watch her as you stand on the lake shore immediately below, and at a certain instant your keen hearing recognizes that the usual frequency of her yell, which is 933 Hz, is shifted by 54.3 Hz.

Chemical energy is a form of energy. a. heat b. kinetic c. potential d. electromagnetic

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

If a star is moving toward earth, it is