Which statements correctly describe theories? Check all that apply. All theories that scientists could discover have already been written.
Theories develop over time as new Scientific evidence is discovered.
Parts of theories cannot be disproved, but new parts can be added.
Theories and laws are the same types of rules about how nature works.
Theories can be changed when new fields of scientific study develop.

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?