a train travels forward 20m/s. a person on the train stands up and walks towards the back of the train at a velocity of 1m/s. what is the resultant of the person velocity

The volumes of a sample of lead and a sample of platinum are the same: 2 cm3. the density of lead is 11.3 g/cm3 and the density of platinum is 21.5 g/cm3. which is an accurate description of their relative masses? a. the masses of the lead and platinum samples are the same. b. the mass of the lead sample is greater than the mass of the platinum sample. c. the mass of the platinum sample is greater than the mass of the lead sample.