Whats the origin of all stars?
a) supernova
b) dwarfs
c) protostars
d) nebulae

What can you increase the strength of an electromagnet by

This is the number of complete movements of a wave per second.

Complete these sentences. if a roller coaster train has a potential energy of 1,500 j and a kinetic energy of 500 j as it starts to travel downhill, its total energy isj. once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 j, and its potential energy decreases to j. when the train reaches the bottom of the track and is traveling along the ground, its kinetic energy isj.