If a 3900 lb vehicle is static and it is hit broad side by a 3400 lb vehicle. With a traveling distance to impact being 35 feet. What would the force and speed necessary be for the 3400 lb vehicle knock or jolt the 3900 lb vehicle 6 feet? Thank you

Rangers51 - I'm assuming you are asking this because you or someone you know was in an accident (in the 3900 pound car) and are trying to figure out the speed of the car who hit you, right? Unfortunately it's impossible to say, given the data you've provided. The answer would depend on the friction between road and tires, were brakes applied, weather conditions (cars slide further on wet roads than dry), and amount of damage to both cars (crumpled sheet metal absorbs a lot of energy). Also, I don't understand what you mean by "traveling distance to impact" - please clarify. Do you mean the 3400 pound car slammed on its brakes and skidded 35 feet before hitting the other car?

Was a police report filed, and did the officer provide any estimate of the speed of the other car?

I can tell you from experience that you don't have to be going very fast to push another cat 6 feet. Last year I broad-sided a Lincoln Town Car when the driver pulled out of a side street without looking. My car weighs about 3900 pounds and hers perhaps a little more. I was initially doing about 30 MPH, stood on the brakes when I saw her pull out, and at impact had probably slowed down to about 15-20 MPH. My car pushed hers a good 6 feet. I suspect her car was totalled, while mine sustained about $6K in damage (paid for by her insurance, of course).