A cruise ship makes its way from one island to another. The ship is in motion compared with which reference point? A. the passengers on the ship

B. the captain of the ship

C. a lighthouse on a nearby island

D. the cargo inside the hull of the ship

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?