General Science Lesson 1.2: Translational Motion - Distance, Displacement, Speed, Velocity, and Acceleration

Flashcards covering core concepts of translational motion: scalar vs vector quantities, distance vs displacement, speed vs velocity (and instantaneous speed), acceleration, frame of reference, and related notation.

What is a scalar quantity?

A physical quantity that has magnitude but no direction; described by a single number with its unit.

What is a vector quantity?

A physical quantity with both magnitude and direction; magnitude describes size and direction indicates orientation relative to a reference frame.

Provide examples of scalar quantities.

Mass, speed, distance, time, density, volume, temperature.

Provide examples of vector quantities.

Displacement, weight, force, velocity, acceleration, momentum, torque.

How is a vector quantity represented visually?

By an arrow; the length represents magnitude; the direction indicates orientation; symbol is a bold capital letter.

Define distance in translational motion.

The total length of the path traveled; scalar; direction is not specified.

Define displacement.

The straight-line change in position from initial to final; a vector with magnitude and direction; Δd = d2 − d1.

Distinguish distance from displacement with an example.

If you walk 5 m forward then 5 m back, distance = 10 m; displacement = 0 m.

Define velocity.

The rate of change of displacement; a vector; v = Δd/Δt; has magnitude and direction; units m/s.

Define speed.

The rate of motion with respect to time; a scalar; s = d/Δt; magnitude only; units m/s or km/h.

What is instantaneous speed?

The speed at a particular instant; read by a speedometer; Δt is very small.

Define acceleration.

The rate of change of velocity; a = Δv/Δt; a vector; positive when speeding up, negative when slowing down.

What does a positive or negative acceleration indicate?

Positive acceleration: velocity increasing; negative acceleration (deceleration): velocity decreasing.

What is a frame of reference?

A physical framework (e.g., ground, room) used to measure position and motion; motion is relative to this frame.

What is position in this context?

The location of an object with respect to a reference frame.

What does Δd represent in displacement formulas?

Δd represents the change in displacement; Δd = d2 − d1.

Difference between distance and displacement regarding direction?

Distance is scalar with no direction; displacement is vector with direction.

What are the SI units for velocity and speed?

Meters per second (m/s); velocity includes direction, speed is magnitude only.

What are the SI units for acceleration?

Meters per second squared (m/s²).