Miriam accidentally drops her cell phone during a call. It falls for 0.5 s before hitting the ground. What is the speed of the phone at 0.5 s? Assume only gravity is acting on it. A. 5 m's B. 10 m/s C. 20 m/s D. 0.5 m/s​

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?