Report the following measurement using three sig figs?

When the volume and number of particles of a gas are constant which of the following is also constant

Aroller coaster is traveling at 13 mi./s when you purchase a hill that is 400 m long and down the hill exonerate at 4.0 m/s squared what is the final velocity of the posterior found your answer to the nearest number

How many grams are there in one megagram