Why do chemists like nitrates?
They are cheaper than day rates, that's why!
The Science Joke Book is an almanac of nerdy jokes to lighten and entertain yourself. Science is treated as a serious business, but it also provides scope for humour like no...
Two cats are sitting on a roof. Which one slides off first?
A. The one with the smaller mu!
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This joke is a play on homophones as "mu" is pronounced like "mew", as in the sound made by a cat. It is represented by the Greek letter µ.
(This joke assumes that the cats are of equal masses and that the cat in question is totally complacent to slide off the roof, making no effort to maintain his position. Strange cat.)
µ must be scientists' favourite letter, as it is used to represent linear mass density, coefficient of friction, dipole moment, mutation rate, chemical potential, etc. It even has a unit {usually of the order of 10^(-6) of SI units} and a subatomic particle (the muon) named after it!
In this joke, µ is meant to represent the coefficient of friction.
I trust the frictional force needs no introduction.
F = µ R, where R is the normal reaction. As we are considering a body on an inclined plane (cat on the sloping roof), this becomes
F = µ mg cosθ,
where mg is the weight of the body, cosθ is the cosine of θ, which is the angle that the roof makes with the ground and µ is the coefficient of friction.
Whether the cat actually slides or not depends on whether the gravitational component pulling the cat down the roof is greater than the frictional force holding the cat in place.
The two cats are of the same mass, they are of the same weight, and they sit on the same roof which makes an angle of θ with the ground in each case.
In that case, force of friction becomes directly proportional to µ.
With a smaller coefficient of friction – a smaller mu – the cat would be less able to hold its position on the roof and more likely to start sliding downward.
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Next time somebody tells you this joke, they'll be met with less friction, because you'll understand it purr-fectly, right?
Did you like this Iron Lithium Neon Joke, er, this FeLiNe pun?
Cos this isn't the last time we make a FeLiNe joke.
