When does radioactive decay occur?

a. when an atom gains electrons

b. when neutrons accumulate in the nucleus

c. when an atom loses electrons

d. when the nucleus decays

Which expression allows you to determine the mechanical advantage of an inclined plane? a. height of plane / input force b. length of plane / input force c. length of plane / height of plane d. height of plane / length of plane

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?