Cows and physics are a joke

A cow and a horse graze in the same trough. The cow proudly showed off: Hey, Brother Ma, I discovered that I am a very great cow. Recently I made a new discovery.

Ma hurriedly asked: Brother Niu, what new discoveries have you made? Don't be so secretive, just say it!

Niu said excitedly: Now I understand why physics is called physics. Do you know who founded physics?

This horse is also knowledgeable. It said: Well, it seems to be a guy named Newton, right?

Niu said: Yes, it’s this guy. Because his contribution to physics was so great, in order to commemorate him, people used his word "niu" on the word "object" in physics. Physics is also a good science.

The horse smiled: Hehe, Brother Niu, I think you only know one, not only the other. How to write the word "wu"? This is indeed the word "Niu", but the other side is the word "Don't". Don't mean anything, you know? It just means no. This means that physics is not a science.

Niu was furious: Bah, you crazy horse! Stay away from me, I have nothing to do with you being a crazy horse! Hey, I'm so great, I actually understood an idiom easily!