1 Kinematics Free Online FlashCards

What does kinematics describe?

Kinematics describes motion without examining what causes it.

Why choose a reference frame to describe motion?

A reference frame defines the perspective from which position and motion are measured.

What is displacement in one dimension?

Displacement is the change in position: $\Delta x=x_f-x_i$. It depends only on the initial and final positions and includes direction.

What does distance traveled measure?

Distance traveled is the total length of the path. It is never negative.

How is average velocity calculated?

Average velocity is displacement divided by elapsed time: $\vec v_{\text{avg}}=\frac{\Delta\vec r}{\Delta t}$.

How is average speed calculated?

Average speed is distance traveled divided by elapsed time. It is nonnegative.

What does instantaneous velocity describe?

Instantaneous velocity describes motion at a particular instant; its magnitude is speed.

How is average acceleration defined?

Average acceleration is the change in velocity per unit time: $\vec a_{\text{avg}}=\frac{\Delta\vec v}{\Delta t}$.

When does one-dimensional acceleration increase speed?

In one dimension, acceleration opposite in sign to velocity reduces speed at that moment; acceleration with the same sign increases it.

How does constant acceleration relate velocity to time?

For constant acceleration, final velocity is $v=v_0+at$, where $v_0$ is initial velocity and $t$ is elapsed time.

Which constant-acceleration equation gives position from time?

For constant acceleration, position is $x=x_0+v_0t+\frac{1}{2}at^2$.

What does the slope of a position–time graph represent?

The slope of a position–time graph is velocity. The tangent's slope at a point gives instantaneous velocity.