What happens to the induced magnetism in the iron bar when the magnet is taken away?

In the first law of thermodynamics, triangle e=q-w, what does q stand for

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?

What is the name of the perceived change in a sound wave’s frequency due to motion between the observer and the sound source?