Heat would best be transfered by conduction between?

Substances that are in direct contact with each other.

Explanation:

Between another substance coming in contact. Known as a conductor

the independent variable, the one that is intentionally manipulated, is whether or not the car hits the barrier.

the dependent variable, the one that you measure the response in, is the distance that the washers travel.

r = ρ x length / area  

ρ = r x area / length  

ρ is in ohm-meters  

in basic units, it is m³kg/s³a²  

i think this is it.