the sears tower in chicago is 443 m tall. joe wants to set the worlds stair climbing record and runs all the way to the roof of the tower. if joes average upward speed is 0.06 m/s, how long will it take joe to climb from street level to the roof of the sears tower? convert your answer into hours

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?