Will swinging a baseball bat create EM waves? It’s my understanding that an accelerating charge is what creates EM radiation. A bat has electrons which have a negative charge. A swinging bat accelerates those electrons. Is it correct to conclude that the bat is therefore generating EM radiation? I guess if the answer is yes then all acceleration of mass generates EM, the earth, cars, etc.
 A: Yes but no.
Yes the acceleration of the charges will create EM waves but first of all the bat is most likely neutral meaning for each wave created by an electron there is also a wave created by a proton. Those waves would destructively interfere with each other, what they create can be more accurately described as noise rather than a wave. But even if your bat had excess charge the acceleration of it would be too low, relatively speaking. What do I mean by "too" small?
Well, consider the formula for the Electric fields of moving charges:
E = Constant * charge * acceleration / distance
https://doi.org/10.1016/j.proeng.2011.05.078
Here is an article on the acceleration of cricket bats, the values they've calculated does not exceed 2gs; I assume it wouldn't be much different for a baseball bat too. So say the bat is not perfectly neutral but has an excess charge of 1 electron, 1.6 * 10^-19 Coulombs that is. The constant is 1/(4piepsilon0*c^2) which is around 10^-7 and we can say we are a meter away from the bat.
E ≈ 10^-7 * 1.6 * 10^-19 2*9.81 / 1 = 3.14 * 10^-25 N/q
Which is significantly low, it is unlikely for your bat to have enough excess charge to create a significant disturbance in the field.
