# Calculating Impact Force

1. Feb 11, 2008

### Fuller

I was wondering if anybody could help me. I need to calculate the impact force exerted on an rov if it collides with a oil well tree. The imformation I have are the mass of the rov = 500 kg, initial velocity othe rov is 1.5 m/s and the oil well tree is a fixed body. Im unsure how to calculate the final velocity of the rov ( do I assume this to be 0?) and on how to calculate the duration of the impact.

2. Feb 12, 2008

### stewartcs

You are looking for the Impulse of the ROV on the tree, so you'll have to estimate how long the contact time is. Mathematically stated...

$$J = \frac{mv}{t}$$

where,

J = the impulse or impact force
m = the mass of the ROV
v = the velocity of the ROV
t = the time of contact between the ROV and the tree

A typical estimate for the time of contact would be $$\frac{A}{v}$$

where,

A = the area of contact

Make sure your units are correct.

CS

3. Feb 12, 2008

### minger

We often cannot get these theoretical values. A couple of years ago, I had a problem where I was to determine if a pipe fell onto a platform, if the platform would break. Obviously this was not something we could test, and I looked all over to try to get something that would help. My boss gave me a couple of copied pages from a 1940 textbook, that looked handwritten, that gave:

Perhaps you could use something like this.