Using following data draw distance –time graph for a moving object, calculate the speed of the object during first 4s from the graph Time (s) 0 2 4 6 8 10 12 14 16
Distance(m) 0 2 4 4 4 6 4 2 0

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?