The speedometer displays the speed, rather than the velocity of the car. Velocity is usually displayed by a GPS unit, and may be in the for of- 22 Mph
at a heading of 355 degrees. A speedometer actually uses the rpm of the wheels to calculate speed, which is why if you put your car's tires off the ground and rev the engine, the displayed speed increases even though you are not going anywhere.
94 electrons. protons and electrons are always the same, but neutrons are different.
