1. The problem statement, all variables and given/known data A friend of mine gave me this problem to solve and I have no idea where to begin: A car weighing 5000lbs traveling at 160km/hr with a payload of 45 kg on the roof hits a wall and stops after crumpling 3 ft. What is the minimum strength of the bond to hold the payload on the car. 2. Relevant equations I have no idea - I converted the weight of the car to 2268 kg but I don't know what use that information is in the broader equation. I think I can use s=vt-(1/2)at^2 and s=ut-(1/2)at^2 to figure out the time it takes for the car to come to a stop and then use the same equation to determine the acceleration of payload - i.e. I think I have to figure out the deceleration of the car and then use that as the acceleration on the payload. Again, I'm not sure what to do with the weight of the payload. I figure I can find out the downward force in Newton meters (441.3) but don't know how to figure out the shear stress applied to the objects to determine the minimum strength of the bond.