A man holds an umbrella vertically up while walking due west with a constant velocity of 1.5 m/s to protect himself from the rain. He can
rotate the umbrella by an angle of 30 degree and still protect himself
from the rain when he stops walking. What is the velocity of the rain?

If this plastic cup is heated to its melting point, what will eventually happen to all the particles in the plastic? a. the particles will begin to move enough that they slide past each other. b. bonds will form and the liquid will become a solid. c. the spaces between the particles will get smaller. d. the particles will change state and become a crystalline solid.

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

At time t=0, a particle is located at the point (3,6,9). it travels in a straight line to the point (5,2,7), has speed 8 at (3,6,9) and constant acceleration 2i−4j−2k. find an equation for the position vector of the particle.