This is why Spidey stretches in the morning

In the movie Spiderman 2 , there's a famous minute or two long scene where Spiderman stops a train . If the initial speed of a five car out of control subway train was around the top speed of the NYC subway (27 m/s), and Spiderman stopped the train in exactly one minute, then what is the magnitude of the force in Newtons that Spiderman exerted on the train as he stopped it?

Details and Assumptions

  • A standard New York City subway car full of terrified passengers has a mass of roughly 40,000 kg.
  • You may assume the acceleration was constant and any other forces are negligible.


The answer is 90000.

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5 solutions

Arya Samanta
May 12, 2014

Going superHERO!

WEll as it was a constantly accelerated system I used v = u + a t v=u+at equation .. where v = 0 v=0 , u = 27 m / s u=27 m/s , t = 60 s e c o n d s t=60 seconds

So a comes out to be 9 / 20 m / s 2 9/20 m/s^2 .

As the train is of 5 cars and each car of mass 40000 40000 kg , so the total mass is \Rightarrow
200000 200000 kg .

Now .... F o r c e = M a Force = M \cdot a

\Rightarrow F = 200000 k g 9 / 20 m / s 2 F = 200000kg \cdot 9/20 m/s^2

\Rightarrow F = 90000 N F =\boxed{90000 N}

So our SuperHERO has to have a force of 90000 N \boxed{90000 N} to stop the train. Watch out the Vedio .

that force work in opposite direction. why not -90000N?

Muhammad Ihsan - 6 years, 1 month ago

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It only asked for the magnitude :)

Steve Gale - 5 years, 7 months ago

I like this step-by-step solution, Thanks....

Sahba Hasan - 7 years, 1 month ago

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Yours Welcome :)

Arya Samanta - 7 years ago

Well, I did exactly the same but didn't actually know that train had 5 cars so my answer went wrong

Shivansh Singh - 3 years, 2 months ago

dont know how to do f divides by t

Nishant Sahoo - 1 year, 1 month ago
Anish Puthuraya
May 11, 2014

Assuming a \displaystyle a is constant (it is given),
Force = M Δ V Δ t \text{ Force} = M \frac{\Delta V}{\Delta t}

F = 5 × 40000 kg × 27 m sec 60 sec F = 5\times 40000 \text{kg}\times \frac{27\frac{\text{m}}{\text{sec}}}{60 \text{sec}}

F = 90000 N F = \boxed{90000N}

After seeing the video : I think thats what Tobey's expressions were when he came to know that Andrew Garfield replaced him (just kidding)

I went the same way but I didn't add 5*...I don't know what the hell five-car is...

Stefan Dimitrijevic - 5 years, 5 months ago

so..preparing for advance...(just saying)..nice answer

Max B - 7 years, 1 month ago

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Well, there is not much use of studying for 10 days. If I couldn't study it for 2 years, then surely I cant do it in such short amount of time. So, Im just studying bit by bit, and concentrating more on preparing my mind (calming my mind).

Anish Puthuraya - 7 years, 1 month ago
Mursalin Habib
May 11, 2014

First notice that a standard New York City subway car full of terrified passengers has a mass of roughly 40000 40000 kg. And Spiderman stops five cars. So the total mass m m Spiderman has to stop is equal to 40000 × 5 40000\times 5 kg or 200000 200000 kg.

Spiderman stops the car in exactly 1 1 minute or 60 60 seconds And he makes the car go from 27 27 m/s to 0 0 m/s in that time.

So, the magnitude of acceleration a a caused on the car is equal to 27 60 \dfrac{27}{60} m/s 2 \text{m/s}^2 .

Now use F = m a F=ma .

Plug everything in you're going to get F = 90000 F=90000 newtons.


I feel like I have solved this problem before.

To the staff, are you working on the Brilliant archive?

Haha I forgot there were 5 cars...

Maddy B - 7 years ago

@Mursalin Habib Sue told me they are indeed working on the archive.

Trevor B. - 7 years, 1 month ago

Yep according to Sue,the archive is currently under construction.

Thaddeus Abiy - 7 years, 1 month ago

Since the train is a five car, the total mass of the train would be 40000 x 5 = 200000 kg. By the formula for momentum, p = mv, the momentum of the train is then 200000 x 27 = 5400000 Ns. Then, using the formula for impulse, Impulse = Fs, the force applied by Spiderman is 5400000/60 = 90000 N.

Tripp Bishop
Nov 1, 2017

I just went with impulse here:

F t = Δ p F\cdot t = \Delta p

F = m a F=m\cdot a , and the mass is given as 4 × 1 0 4 k g 4 \times 10^{4}kg . Δ p = p f p 0 \Delta p = p_{f} - p_{0} and since we know spidey stops the train, the final momentum is simply 0. We can easy calculate the initial momentum: p o = m v o = 4 × 1 0 4 k g 27 m / s = 5.4 × 1 0 6 k g m / s p_{o} = mv_{o} = 4 \times 10^{4}kg \cdot 27m/s = 5.4 \times 10^{6}kgm/s , so the change in momentum is simply 5.4 × 1 0 6 k g m / s -5.4 \times 10^{6}kgm/s .

Now we can calculate the acceleration using a = Δ p m t a = \frac{\Delta p}{m\cdot t} . Plugging in numbers we arrive at: a = 5.4 × 1 0 6 k g m / s 2.0 × 1 0 5 k g 60 s = 0.45 m / s 2 \frac{-5.4 \times 10^{6}kgm/s}{2.0 \times 10^{5}kg\cdot 60s} = -0.45m/s^{2}

Now we can solve for the magnitude of the force required: F = m a = 2.0 × 1 0 5 k g 0.45 m / s 2 = 9 × 1 0 4 N \left \| F \right \|=ma = 2.0 \times 10^{5}kg \cdot 0.45m/s^{2} = 9 \times 10^{4}N

Definitely simpler ways to get at the answer, but it seemed like a fun impulse problem. Hope that was useful. Cheers!

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