1670: Laws of Physics

2016-04-21T07:38:49Z

Tasar: Undo revision 118435 by Tasar (talk)

{{comic
| number = 1670
| date = April 20, 2016
| title = Laws of Physics
| image = laws_of_physics.png
| titletext = The laws of physics are fun to try to understand, but as an organism with incredibly delicate eyes who evolved in a world full of sharp objects, I have an awful lot of trust in biology's calibration of my flinch reflex.
}}

==Explanation==
[[Black Hat]], being {{w|Black Hat}}, is deliberately perverting a classic physics demonstration. In the normal version of the demonstration, a heavy ball on a pendulum is pulled to one side until it is almost, but not quite, touching the demonstrator's nose or chin — in this comic, Black Hat is the only one in the right position for the experiment. A ''very trusting'' volunteer could safely stand at the other end of the pendulum's arc, if the same distance from the middle were correctly measured and the pendulum anchored securely. When the ball is released at rest, it swings down and away, then back up to (almost) the same distance in the arc from where it started — but ''never'' (by the laws of physics) farther than where it started. If the volunteer doesn't lean in, the heavy ball will never hit them in the nose. (Sample videos: [https://www.youtube.com/watch?v=xXXF2C-vrQE], [https://www.youtube.com/watch?v=i2GdY1OlDpA].)

In this comic, since Cueball is not standing at the edge of the ball's movement, but rather at the base of its swing, he is about to get a rude surprise.

The title text refers to the fact when someone flinches during the pendulum experiment, they are commonly accused of not having faith in the laws of physics. Randall is rebutting this argument by stating that, rather than not having faith in science, he is actually in tune with it, specifically the biological processes that led to the flinch reflex. His eyes and his flinch reflex have been calibrated through millions of years of evolution. To instantly dismiss your body's natural reaction when a heavy object comes quickly towards your face does not give enough credit to these mechanisms that successfully kept you (and every one of your ancestors) alive. In other words, while flinching may indicate doubt of the laws of physics, it may equally well indicate trust in the laws of biology.

==Transcript==

:[Black Hat is standing on a ladder, holding a heavy ball attached to a line from above. Cueball stands beneath, where if the ball swings it will smack him right in the face.]
:Black Hat: Okay, hold still.
:Black Hat: And remember, if you ''really'' believe in the laws of physics, you won't flinch.

{{comic discussion}}

[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Cueball]]

1670: Laws of Physics

2016-04-21T07:37:34Z

Tasar: Explain effects of curve in rope.

{{comic
| number = 1670
| date = April 20, 2016
| title = Laws of Physics
| image = laws_of_physics.png
| titletext = The laws of physics are fun to try to understand, but as an organism with incredibly delicate eyes who evolved in a world full of sharp objects, I have an awful lot of trust in biology's calibration of my flinch reflex.
}}

==Explanation==
[[Black Hat]], being {{w|Black Hat}}, is deliberately perverting a classic physics demonstration. In the normal version of the demonstration, a heavy ball on a pendulum is pulled to one side until it is almost, but not quite, touching the demonstrator's nose or chin — in this comic, Black Hat is the only one in the right position for the experiment. A ''very trusting'' volunteer could safely stand at the other end of the pendulum's arc, if the same distance from the middle were correctly measured and the pendulum anchored securely. When the ball is released at rest, it swings down and away, then back up to (almost) the same distance in the arc from where it started — but ''never'' (by the laws of physics) farther than where it started. If the volunteer doesn't lean in, the heavy ball will never hit them in the nose. (Sample videos: [https://www.youtube.com/watch?v=xXXF2C-vrQE], [https://www.youtube.com/watch?v=i2GdY1OlDpA].)

In this comic, since Cueball is not standing at the edge of the ball's movement, but rather at the base of its swing, he is about to get a rude surprise. However, Black Hat is also not safe, since the rope of the pendulum is not held tight at the moment of release. If the ball does not lose a lot of energy in its swing to the right and back (for example by hitting Cueball), it will on its leftmost point reach the same height it has now, but with a tight rope, and thus arrive a little to the left. In particular it would probably hit Black Hat somewhere in his stomach trying to reach that point.

The title text refers to the fact when someone flinches during the pendulum experiment, they are commonly accused of not having faith in the laws of physics. Randall is rebutting this argument by stating that, rather than not having faith in science, he is actually in tune with it, specifically the biological processes that led to the flinch reflex. His eyes and his flinch reflex have been calibrated through millions of years of evolution. To instantly dismiss your body's natural reaction when a heavy object comes quickly towards your face does not give enough credit to these mechanisms that successfully kept you (and every one of your ancestors) alive. In other words, while flinching may indicate doubt of the laws of physics, it may equally well indicate trust in the laws of biology.

==Transcript==

:[Black Hat is standing on a ladder, holding a heavy ball attached to a line from above. Cueball stands beneath, where if the ball swings it will smack him right in the face.]
:Black Hat: Okay, hold still.
:Black Hat: And remember, if you ''really'' believe in the laws of physics, you won't flinch.

{{comic discussion}}

[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Cueball]]

explain xkcd - User contributions [en]

1670: Laws of Physics

1670: Laws of Physics