Next, I need the mass. Each car has an empty mass of 26,000 kilograms and a capacity of 34 seats, or 123 total passengers. From the clip, the train looks pretty crowded, but not at full capacity. Let’s just say there are 60 people per car, and each rider has an average mass of 70 kilograms.
Finally, I need the total number of train cars. We never get a perfect shot, but I’m going to guess there are five cars. That puts the total mass at 151,000 kilograms. Factoring in this mass and the acceleration, we get a stopping force of 113,000 newtons.
That’s the total force pulling on the train to slow it down. But remember, there are webs on both sides of the train. Since Spider-Man holds onto webs on both sides, he’s essentially just exerting a force equal to the tension in the web. That means that he’s only exerting a force that’s half the total value of the stopping force.
The same thing happens when you pass a string over a pulley: It allows you to double your pulling force. (Spidey is essentially acting as the wheel in the pulley system.) Spidey’s exerted force would be half of the 113,000 newtons, or 56,500 newtons. If you want to convert that to imperial units, it would be 12,700 pounds. That’s like holding up a male African elephant. You can see my calculations here.
I’m going to put the Tobey Maguire Spidey strength at a value of at least 56,500 newtons. Of course, we don’t know if that’s his maximum limit, but it’s at least a starting value. Also, I have to confess that I might have cheated. I assumed that the force that Spider-Man exerts on the train is constant. That’s probably not the case. If spiderwebs are like rubber bands, bungee cords, and most stretchy things, the more you stretch them, the greater the force it takes to hold on to or pull them. But since I don’t have any evidence that these webs behave like bungee cords, I’m just going to stick with my constant-force estimation.
Holding a Splitting Ferry Together
Now we can move to Holland’s version in Spider-Man: Homecoming, which you can see in this clip. After an alien weapon goes off and splits the Staten Island Ferry right down the middle, Spider-Man does his best to patch the boat up with his webs to prevent it from sinking. But it slowly starts to separate, with the two halves cracking lengthwise as some of the webs holding them snap apart. In a desperate move, he grabs webs attached to both sides and tries to pull the ferry back together. I’ve drawn a sketch of the important part (not to scale).
Illustration: Rhett Allain