Okay i need with this. we are just beginning this cross multiply thing again and i forgot how to use it. he was very vague about it, here is the question.

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?

You throw a baseball directly upward at time =0 at an initial speed of 14.9 m/s. what is the maximum height the ball reaches above where it leaves your hand? ignore air resistance and take =9.80 m/s2.

Ihave this 50 question test the layer of earth's atmosphere where atoms and molecules escape into space is referred to as the a) exosphere b) ionosphere. c) mesosphere d) thermosphere