Which scientist discovered the two radioactive elements radium and polonium?

Ball b is hanging from an inextensible cord. an identical ball a is released from rest when it is just touching the cord and drops through the vertical distance h a 5 8 in. before striking ball b. assuming e 5 0.9 and no friction, determine the resulting maximum vertical displacement h b of the ball b

In a given chemical reaction, the energy of the products is greater than the energy of the reactants. which statement is true for this reaction?

What are the factors that affect the resistance of a wire?