Two spaceships are traveling past earth at 90% of the speed of light in opposite directions (i. e., they are approaching each other). one turns on a searchlight, which is seen by scientists aboard the other. what speed do the scientists measure for this light (c = speed of light in a vacuum)?

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance. what is its vertical displacement (in m) after 6 s?

The x-coordinate of a particle in curvilinear motion is given by x = 3.1t3 - 4.9t where x is in feet and t is in seconds. the y-component of acceleration in feet per second squared is given by ay = 2.3t. if the particle has y-components y = 0 and vy = 5.0 ft/sec when t = 0, find the magnitudes of the velocity v and acceleration a when t = 1.8 sec. sketch the path for the first 1.8 seconds of motion, and show the velocity and acceleration vectors for t = 1.8 sec. answers: v = ft/sec a = ft/sec2

Avolcano erupts next to a grassland area in a valley. a. describe three ways in which material released by the volcano could impact the grassland area. b. describe three ways in which the grassland ecosystem could recover after a volcanic eruption.