6. With what velocity must a 0.58 kg softball be moving to equal the momentum of a 0.45 kg baseball moving at 21 m/s?

Which statements best describe the work of marie and pierre curie? check all that apply. they discovered radioactivity. they came up with the term “radioactivity.” they conducted experiments with uranium-containing minerals and pure uranium. they conducted experiments with uranium-containing minerals and photographic plates. they discovered two new radioactive elements.