How long does it take a earth to rotate on its axis?

Why are some galaxies’ spectra blueshifted rather than redshifted? question 4 options:

If 2 moles of co_2 at 2l and 500k are expanded reversibly to 20l, more work can be obtained from an adiabatic process than from an isothermal process. is the above statement true or false?

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?