Alight-year is the distance light travels in one year, at a speed = 2.998 x 10^8 m/s.

(a) how many meters are there in 1.00 light years?
(b) an au is the average distance from the sun to the earth, 1.50 x 10^8 how many au are there in 1.00 light-year?
(c) what is the speed of light in au/h?

For waves in the ocean, the medium of the waves is a. air b. water c. energy d. a passing boat

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 you put a helium-filled balloon in the refrigerator, what will happen?