Answer: That's air resistance.
Explanation: Well, air resistance is an upward force exerted on falling objects.
( I hope this helped <3 )
The problem is basically asking us to find a way to find the sound intensity I, in terms dependent on the sound level and the reference intensity
.For this purpose we can start from the unit used in the scale logarithmic decibel, that is

Where
I = Acoustic intensity on the linear scale
Hearing threshold
Using the logarithmic properties of the exponents the above expression can be described as:

that is the expression or technique to find the intensity of sound.
When the ruler is broughı near the inetal knob, it repels electrons in the metal. Electrons move away froni the ruler and down the metal rod. The knob now has a positive charge. The thin pieces of metal foil at the bottom of the metal rod now have a negative charge.
Because the box keeps going straight at the same speed, while the seat under it speeds up, slows down, or changes direction.