Infrasound sound is any sound that are below the sound a human can hear, elephants use it to communicate with other elephants.
"Light year" is a distance, not a speed. It's the distance light travels in one year, at the speed of 299,792,458 meters per second.
The piece of paper has less mass and will glide down the window, whereas the textbook will go straight to the ground. Since the textbook has more mass and less ways of it being able to 'glide' the textbook will hit the ground first.
Answer:
18.6012339739 A
Explanation:
= Vacuum permeability = 
L = Length of wire = 55 cm
N = Number of turns = 4000
I = Current
Magnetic field is given by

The current necessary to produce this field is 18.6012339739 A