Please helppp As you move the trash can to barricade the school door you hear footsteps coming from inside the school. They seem to be coming from the lunchroom. The distance to the lunchroom is 300 m and the time it takes you to get there is 12 seconds. What is the speed you are traveling at?

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?