We don't know why some compounds reflect red and some reflect blue. We don't even know why glass is translucent.
Fluorescence suggests an answer. This is when you, for example, shine a green light on a rock and it reflects purple. The explanation is that the light energy stimulates...
This is a slight rewrite of the above proof, which used "FNx" where "FN1x" should have been employed:
The torque equation is fairly obvious: FN1*0.07 - 220*0.05 + FN2*0.04 = 0.
The obvious choice for the second equation would be to net out the vertical forces, but this involves three...
The torque equation is fairly obvious: FN1*0.07 - F*0.05 + FN2*0.04 = 0.
The obvious choice for the second equation would be to net out the vertical forces, but this involves three quantities. Better to find the two horizontal forces on the rod from the stoppers. These exist because the...
If you reason "220 minus 5/11 of itself is 120", you get the value of 120 Newtons for FN1. Then you can use the 4 cm to 7 cm proportion to get 68N for FN2. The 11 in 5/11 comes from the sum of 4 cm and 7 cm.
This works, but I don't know why.
The equations that were derived above...