When the secondary is open there is no current flow thus it consumes no power, power = voltage*current (there is also an additional term 'power factor' that we can neglect for this example).
When the secondary is attached to a load, the primary coil feeds the secondary power through induction...
Air (the gas) contains water vapor. When this rapidly gas travels from high to low pressure it expands which condenses out the water vapor. The high pressure is ahead of the airfoil (wing or rear stabilizer) - the low pressure is after. When atmospheric conditions are correct, this difference...
My take: The hypothesis holds true if each car is identical with opposite and equal velocities, which causes a perfect head on collision; meaning all potential energy of both vehicles is exhausted equally, to zero at impact. No spin - just pancake.
The difference in the "30 mph and 40 mph"...
The way I remember it ('88 grad) - you have two types of friction:
Static - this is related to the force necessary to get a stationary object to move from rest.
Dynamic - this is related to the force necessary to sustain a moving object at a constant velocity. Does the question pertain to...