Ship a is located 4.0 km north and 2.5 km east of ship b. ship a has a velocity of 22 km/h toward the south, and ship b has a velocity of 40 km/h in a direction 37° north of east.
(a) what is the velocity of a relative to b in unit-vector notation with ˆi toward the east?
(b) write an expression (in terms of ˆi and ˆj) for the position of a relative to b as a function of t, where t 0 when the ships are in the positions described above.
(c) at what time is the separation between the ships least?
(d) what is that least separation?

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.

Acombination reaction is when two or more combine to form one product. a decomposition reaction is when a substance breaks down into two or more simpler substances in a chemical reaction.

The mass of the sun is 1.99×1030kg and its distance to the earth is 1.50×1011m. what is the gravitational force of the sun on the earth?