if I have a sine wave signal for a duration of only a few seconds, the Fourier transform will show me, that this signal corresponds to a range of frequencies. Why is this the case? I do understand that every signal is composed of sine waves, even this sine wave pulse, but I don't get the intuitio...

Night-blooming cereus are plants that only bloom at night. Their light-sensitive cells must be able to tell the difference between sunlight, and sunlight reflected off the moon. What is the physical difference between sunlight, and sunlight that has been reflected? Can we say the difference is in...

When I leave my room I walk down three flights of stairs releasing about 7kJ of potential energy. Where does it go? Is it all getting dispersed into heat and sound? Is that heat being generated at the point of impact between my feet and the ground, or is it within my muscles? Related question, ho...

How does a home appliance limit the amount of current that flows through it? Are there some resistors set up in series in order to cut down the current flow before it actually reaches the device? Assuming that there are 15 Amps under 240V in each socket, most of the appliances but burn/get dest...

Imagine a supermassive hollow shell in space, and also imagine there is an object at the center of this shell. How does the force of gravity affect the body inside the shell? My reasoning is that the shell will pull outward on the body equally in all directions. Now do the forces cancel out essen...