Physics: Collision between two objects, 9000lbs and 2000lbs.?

Question

What is the better option for the larger object in this situation and why. The collision between the two objects can not be avoided and the collision is a straight on. If an object weighing 9000lbs is traveling at 40mph and approaches an object weighing 2000lbs, should the larger object continue on its trajectory and speed at 40mph and collide with the smaller object or should it slow down to 20mph before the impact?

Answer 1

I guess the criteria will be the amount of energy converted to heat in the collision. The more energy converted, the bigger the ouch.
Let's make the collision perfectly inelastic
9000*40=11000*v
v=32.73 mph
or
9000*20=11000*v
v=16.36

9000 pounds = 4082 kg
2 000 pounds = 907 kg
40 mph = 18 m/s
20 mph = 9 m/s
32.73 mph = 14.63 m/s
16.36 mph = 7.3 m/s

let's look at energy
.5*4082*18^2-.5*4909*14.63^2
136000 J
versus
.5*4082*9^2-.5*4909*7.3^2
34500 J

The difference in energy is staggering, it is best to slow down, it lowers the violence of the crash by
75%

j