is it a solid or a fluid?

[John Gutmann]

i remember a while ago watching this thing on tv that was showing new shocks in a car, i dont remember what kinda car, but the stuff in the shocks was a substance that either reacted to electrical current or magnetic fields, i am unsure about which one it was, but when it reacted it would harden up

i was reading a post buy FIRST_jersey kid in the educational robotics about a brake system then they were going to try next year, and if you wanted to make brakes with that stuff would it be legal in terms of FIRST's rules and regs?

for the system you could maybe do multiple pieces in a cylinder that were cut out of some thickness of metal that would be low drag and have that cylinder full of that substance so that when you apply either current or a magnet field(i dont remember what one) it would harden up and not beable to rotate