Kinematics and Dynamics

Kinematics

Describes how a body moves.

Dynamics

Accounts for motion in terms of forces.

Translation

Motion in a straight line.

Displacement

Difference between initial and final position.

Velocity

Speed and direction of a moving object.

Acceleration

Change in velocity over a unit of time.

Vector quantities

Described by their magnitude and direction.

Scalar quantities

Described by their magnitude and approximate unit.

Reference point

A starting point to locate a place.

Position

Distance in a direction from a reference point.

Complete description of position

Includes distance, direction, and reference point.

Positive direction

The reference direction is positive (+).

Speed

Measure of distance traveled in a unit of time, calculated by dividing distance by time; SI unit is m/s.

Constant speed

Same distance traveled each second.

Instantaneous speed

Speed at a specific instant in time.

Average speed

Total distance traveled divided by total time taken.

Acceleration representation

By an arrow indicating direction.

Speed-time graph

Shows how speed changes over time.

Upward slope on speed-time graph

Indicates the object is speeding up.

Downward slope on speed-time graph

Indicates the object is slowing down.

Mark's total distance traveled (25.0 km to mall and 25.0 km back home).

50.0 km

Mark's displacement after trip (back to starting point).

0 km

Pablo's average speed (7 km in 30 mins).

14 km/h

Justin's time to walk 250 m at 1.5 m/s.

166.67 s

Speed of a boat (travels 80 km in 2 hours).

40 km/h

Jeno's time to ride 45 km at 5 kph.

9 hr