No, the noun skateboard is a common noun, a general word for any skateboard of any kind.A proper noun is the name of a specific person, place or thing; for example, a Sk8mafia Skateboard.
When you increase your velocity on a skateboard it is harder to stop because of momentum.
When you increase your velocity on a skateboard it is harder to stop because of momentum.
momentum
This is an example of inertia. Inertia is the tendency of an object to resist changes in its motion. In this case, the skateboard's velocity creates momentum that makes it harder to stop suddenly.
This is an example of inertia, the tendency of an object in motion to stay in motion. As you increase your velocity on a skateboard, your momentum also increases, making it harder to stop because of this inertia.
This is your principal target. The principal goal must be achieved.
Bernoullis principle
example: I am entrusting you with my skateboard.
There are a variety of designs which could be great for a girl's skateboard. A rose or a Hello Kitty logo, for example, are good options. For more ideas, visit the girl's skateboard section on Zazzle.
Airplane,ventrimeter,andpump
http://en.wikipedia.org/wiki/Bernoulli%27s_principle#Real_world_application