Suppose the half-life of an isotope is 10 years. after how many years will half of this isotope have decayed into its daughter elements?

5 years
10 years
20 years

Calculate the estimated density of each ball. use the formula d = m/v where d is the density, m is the mass, and v is the volume. record your calculations in table a of your student guide. given that the density of water is 1.0 g/cm3, make a prediction about whether each ball will float in water. record your prediction in table a. what is the estimated density of the table tennis ball? record your answer to the nearest hundredth