Relative Motion and Dynamics Practice Flashcards

Vocabulary and key concepts regarding relative motion, multi-dimensional kinematics, and dynamics based on the lecture transcript.

Relative Motion

The concept that the only way to define motion is by a change in position relative to a specific reference point.

Earth's Rotational Speed

The movement of an observer at approximately $1000\,\text{miles per hour}$ relative to the center of the Earth.

Earth's Orbital Speed

The velocity of the Earth as it moves around the Sun at over $66,000\,\text{miles per hour}$.

Reference Frame

A coordinate system used to relate an object's speed, such as a fixed point on a train vs. a fixed point on the Earth.

Perpendicular Kinematics

The principle of considering each dimension separately in multi-dimensional problems, using a specific shared variable to link them.

Time ($t$)

The critical crossover variable in multi-dimensional kinematics problems that is shared between separate dimensions.

Independence of Motion

The concept that horizontal and vertical directions (such as a swimmer's time to cross a river) are unaffected by perpendicular vectors like a current's downstream push.

Coefficient of Friction ($\mu$)

A value used in dynamics problems, such as $\mu = 0.2$ in the block examples, to calculate the force of friction ($F_f$).

Free Body Diagram (FBD)

A visual representation of all forces acting on an object, including normal force ($F_N$), gravity ($F_g$), friction ($F_f$), and tension ($F_T$).

$$v_{ac}$$

The velocity of an object relative to the ground.

$$v_{ab}$$

The velocity of an object relative to a moving reference frame (such as a boat relative to water).

$$v_{bc}$$

The velocity of a moving reference frame relative to the ground (such as water moving relative to the ground).

Vector Addition

The process of breaking velocities into $x$ and $y$ components ($v_x$ and $v_y$) and adding them to find a net magnitude and direction.

Summary of Dynamics Concepts

The principles that $X$ and $Y$ directions are independent, $\Sigma F = ma$ applies in both directions, and relative motion is found by adding vector components.