4 ms·
25mph is >150% of the energy at 20mph. It's a big increase.
by hgomersall 5y ago
25mph is >150% of the energy at 20mph. It's a big increase.
- FabHK 5y agoAnd not only that. In a situation where, with 20 mph, you can just come to a complete stop before the child, with 25 mph initially you'd hit it with 15 mph. vr = (c^2 - 1)^0.5 v1 where v1 is the original slow speed with which you'd come to a standstill just before the obstacle, and v2 = c*v1 is the faster speed, and vr the speed with which you hit the obstacle coming in with the faster speed (assuming you hit the brakes at the same spot, and constant deceleration).
- hgomersall 5y agoIndeed, as an interesting aside it's a 3-4-5 triangle. 25^2 - 20^2 = 15^2