Destructive interference occurs in photodiode detectors when direct and scattered light rays take paths to the photocell that differ in phase

Why should seat belts not be mandatory quick plz

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?

Awave has a wavelength of 7 mm and a frequency of 19 hertz. what is its speed?