What is the term for the remains of things found in rock

Asher cycles 12 miles in 16 hours. what is his speed?

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

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?