Heat, kinetic energy loss.
Acceleration = (change in speed) / (time for the change)
- 4.1 m/s² = (-9 m/s) / (time for the change)
Time for the change = (-9 m/s) / (-4.1 m/s²) = 2.2 seconds
It conducts electricity. This is because the electrons are able to move around more for it has gained energy, after being heated.