# Homework Help: Physics question about Spiderman 2 Train Scene

1. Jun 30, 2014

### Connah

Hi, we've recently been set a task by our physics teacher to try and calculate the Young's Modulus of Spiderman's webs in the train stopping scene of Spiderman 2. Doing research on the mass of the carriage + passengers, calculating forces from that and also using things like the velocity, acceleration/deceleration, length and extension of the webs, number of webs, time taken to stop and distance travelled. So far I have ΔL of the webs to be 600m, the unstretched length of each web to be 16m approx cross-sectional area per web to be 3.14x10^-4 m^2, mass including passengers of the 6 carriages to be 164,637.4kg, final velocity as 0m/s, initial velocity (at time he fires first web) as 35.75m/s and the time between firing first web and coming to a stop as 30 seconds. Also the deceleration as 1.192m/s^2 (or -1.192, I forget if I need the minus or not). Also there are 16 webs in total, assumed to be identical. - P.S I've had to calculate every one of these values they weren't given, just in case you think I'm lazy :)

I'm guessing I may need the SUVAT motion equations? Definitely equations for tensile stress and strain, and the basic force and speed equations. Obviously I may be wrong which is why I'm asking for some input x)

I haven't attempted much of it yet apart from working out almost every value I can, I need help working out how you would use deceleration to work out the force on the webs as they're horizontal and I'm used to just weights hanging off vertical supports but I would assume it's more or less similar? I'm also not sure how to get the stress and strain with there being 16 webs in total I'm just a little stuck but I would appreciate some expertise here with helping me solve this problem. I would guess the answer to be a little unrealistic, too, based on some values to be approximate and the fact its a Spiderman movie. Thanks :)

Last edited: Jun 30, 2014
2. Jul 1, 2014

### Simon Bridge

You can use suvat equations, or you could try conservation of energy assuming all the initial KE of the train ends up stored in the web.

3. Jul 1, 2014

### BiGyElLoWhAt

Is this the scene where the train car's falling and almost crashes onto a boat?

Here's a list of equations that involve youngs modulus, with respect to both force and energy.
http://en.wikipedia.org/wiki/Young's_modulus#Calculation

4. Jul 1, 2014

### Orodruin

Staff Emeritus
I would guess this is the intended scene:

Last edited by a moderator: Sep 25, 2014