The density of water is about 1000 kg/m3 and the density of air is about 1 kg/m3. Using only your own everyday knowledge quantified (and your personal measuring sticks), estimate the mass of blood that is pushed out of the heart in each heartbeat and the mass of air that is pushed out of your lungs with each breath. Be sure to carefully explain your reasoning and justify your estimations so that a reader can determine that it is plausible that you know the numbers you have come up with and that they can be trusted.