Which of the following laws states that the momentum of a set of objects is the same both before and after a collision? A.
The law of conservation of momentum

B.
The law of conservation of energy

C.
Newton's first law

D.
Newton's second law

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?

What are the necessary conditions for fusion?