4. which statement best describes the movement of particles when a wave travels through a medium? the particles are (10 points) a. moved along in a forward motion with the wave as it travels through the medium. b. gathered by the energy of the wave and move along in the direction of the wave. c. permanently displaced in a direction opposite to the direction of the wave. d. temporarily displaced and return to their normal position when the wave passes.

Amodel rocket with a mass of 0.212 kg is launched into the air with an initial speed of 84 m/s. how much kinetic energy will the rocket have at a height of 214 m? assume there is no wind resistance. 634 j 303 j

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".

Which of these are physical changes in matter? check all that apply. boiling water a pencil being sharpened exploding dynamite freezing water rotting cheese