AP Physics C - Temp

projectile

An object that moves with only the force of gravity acting on it.

trajectory

The flight path that an object follows. For projectiles, this path is in the shape of a parabola.

range

The horizontal distance a projectile travels before hitting the ground.

t apex (time to apex)

The time it takes a projectile to reach its highest point

accuracy

How close your observed (or measured) values are to the accepted or "true" value.

significant digits

Those numbers in a measurement that you know are exact plus one additional digit that can be reasonably estimated.

systematic error

A known problem that causes your measurements to be different from what they should be by a consistent factor. It is possible to correct for this type of error. An example would be a clock set on purpose to run 5 minutes fast.

uncertainty (or random error)

Errors that result mainly from the measuring device and the person measuring. They are uncontrollable events that cannot be eliminated. [This is what we saw when we all measured the same object in class but got slightly different results.]

particle

An object in physics (such as a car) represented by a single point. It signifies the object's center of mass and is used to simplify solving problems.

displacement

A vector quantity that shows the change in an object's position. It measures the straight line distance (and its direction) between an object's initial position and its final position.

∆x = xf- xi

average velocity

The change in position (which is displacement) divided by the change in time. It is a vector and can be positive or negative.

average acceleration

The total change in velocity divided by the total change in time. It is a vector and can be positive or negative.

free fall

A falling object whose acceleration is caused only by the force of gravity (no other forces acting on it).

acceleration due to gravity

The rate at which an object accelerates on a celestial body due to the force of gravity that acts on the object. On Earth, this value is 9.81 m/s^2. This value differs depending on the celestial body and is represented by the letter g.

scalar

A quantity that has only magnitude. These quantities require only one piece of information to describe it. Examples include mass, time, temperature, speed, etc.

vector

A quantity that has both magnitude and direction. These quantities require two pieces of information to describe it. Examples include velocity, force, momentum, displacement, etc.

relative velocity

The velocity of a body as it appears with respect to another body, which is regarded as being at rest.

unit vector

A vector that has a magnitude of 1 with no units. It's only purpose is to identify the direction along each axis: x, y, and z shown as i, j, and k.