Weight equals mass times gravitational acceleration=400N, so mass=400/9.8=41kg approx.
B. Mentally represent their environment
Answer:
Accelerating charges.
Explanation:
Electromagnetic waves are waves produced by the vibration of both electrical and magnetic fields.
This interaction produces an energy source that does not require any medium to propagate.
To produce electromagnetic waves, electric and magnetic fields must be vibrating.
An electric charge produced when vibrating under voltage will produce electromagnetic waves. This is the same for all sources of these waves.
The sun produces electromagnetic waves. A lot of human activities also does this.
Answer:
The torque about the origin is 
Explanation:
Torque 
is the cross product between force 
and vector position 
respect a fixed point (in our case the origin):
There are multiple ways to calculate a cross product but we're going to use most common method, finding the determinant of the matrix:
![\overrightarrow{r}\times\overrightarrow{F} =-\left[\begin{array}{ccc} \hat{i} & \hat{j} & \hat{k}\\ F1_{x} & F1_{y} & F1_{z}\\ r_{x} & r_{y} & r_{z}\end{array}\right]](https://tex.z-dn.net/?f=%20%5Coverrightarrow%7Br%7D%5Ctimes%5Coverrightarrow%7BF%7D%20%3D-%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%20%5Chat%7Bi%7D%20%26%20%5Chat%7Bj%7D%20%26%20%5Chat%7Bk%7D%5C%5C%20F1_%7Bx%7D%20%26%20F1_%7By%7D%20%26%20F1_%7Bz%7D%5C%5C%20r_%7Bx%7D%20%26%20r_%7By%7D%20%26%20r_%7Bz%7D%5Cend%7Barray%7D%5Cright%5D%20)
