(8c1p14) Time standards are now based on atomic clocks. A promising second standard is based on pulsars, which are rotating neutron stars (highly compact stars consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio beacon that sweeps briefly across Earth once with each rotation, like a light-house beacon. Pulsar PSR 1937 + 21 is an example, it rotates once every 1.55780644887275 ± 3 ms, where the trailing ±3 indicates the uncertainty in the last decimal place (it does not mean ±3 ms). How many times does it rotate in 3.50 days?
What is the mass of gasoline (? = 0.680 g/cm3) in a 94.6 L gasoline tank? (kg)