June 19, 2011


What determines how high you can leap? Two things: your mass and the force your leg muscles supply to the ground. Taking the Second Law of Motion into account, they determine how much acceleration you can achieve as you lift off the ground. Once you are no longer in contact with the surface, the only force acting on you is Gravity, which decreases your acceleration as you ascend. So there are two vectors we have to concern ourselves with: the initial force that gets you airborne, and the deceleration of gravity that eventually halts your ascension.

v^2 = 2gh gives the height h you will climb, and g represents the deceleration due to gravity.


As you might, or might not have noticed, nowhere does the final height that you achieve depend on your mass. Big or small, if you start off with a velocity v and the only thing pulling you back to earth is gravity, then your jump height depends only on the deceleration due to gravity g and your total velocity v. Of course, there is another acceleration that enters into the leap - that provided by your leg muscles at the start of the jump. And this acceleration depends on the mass of the jumper. Using the second law of motion, that force equals mass times acceleration [F=ma] it is clear that for a given force, F, the heavier a person is, the less of an initial velocity he will achieve.
Which means a lower height h that said person will be able to attain.

I was bitten by a radioactive spider. I can jump as far as a spider can.

It's not that spiders are such great leapers that they can jump many times their body length. Rather, it's that small insects have tiny muscles (small force), but they only have to lift an equally tiny mass to leap one meter, which just turns out to be many times larger than their sizes. Humans have much bigger muscles than insects, and can output much greater forces, however they also have to lift much heavier masses, so the net effect is that the range/height that they can jump is also about one meter.

TL;DR - F=ma demonstrates how Spiderman's jumping abilities are pure fiction.


  1. Aww.. I was hoping one day I'd be jumping like Spiderman :(

  2. why is this so much easier to understand then when i was in high school..
    maybe because of spider-man

  3. I love how Physics defy the superpowers of action heroes. Never got into the whole superhero thing with Batman/Superman/Spiderman.

  4. We just have to accept that as far as animals go, we have no real physical outstanding features. A simple dog will kick our ass at running, kangaroo would beat our best distance jumper, and a gorilla could break every bone in our best fighter.

  5. Hmmm, this is actually an interesting piece of physics I didn't quite understand before. Basically, gravity has less effect on a smaller mass, which allows small insects (i.e., spiders) to propel themselves further?

  6. haha very interesting, i always love these interesting facts about physics!
    and i loved the TL;DR, straight to the point!

  7. That free jumper is hardcore. Total pro!

  8. This doesn't disprove Spiderman is in the 20 ton class strength so if he can lift that much his tiny mass would b no problem

  9. This doesn't disprove anything ur not taking into account that spider nab had super strenghth so he can lift ten tons but has the relative size and msss of a human so of course he can jump far...


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