8th Grade Science Study Guide: Speed, Velocity, and Acceleration Concept Review Questions

Speed

The rate at which an object moves, calculated as distance divided by time.

Velocity

Includes both speed and direction.

Acceleration

The rate of change of velocity over time.

Acceleration formula

Calculated using the formula a = Δv / Δt, where Δv is change in velocity and Δt is change in time.

SI unit for speed and velocity

Meters per second (m/s).

SI unit for acceleration

Meters per second squared (m/s²).

Positive acceleration

When an object is speeding up.

Negative acceleration (deceleration)

When an object is slowing down.

Instantaneous speed

Speed of an object at a specific moment.

Average speed

Total distance traveled divided by total time taken.

How does direction affect velocity?

A change in direction changes velocity, even if speed remains the same.

Constant speed and changing velocity

An object moving in a circular path has constant speed but changing velocity.

Acceleration at constant velocity

Zero acceleration, as there is no change in velocity.

Distance-time graph for speed

The slope of the line represents speed; a steeper slope means a higher speed.

Velocity-time graph for acceleration

The slope of the graph represents acceleration; a positive slope means speeding up, and a negative slope means slowing down.

Total distance

The entire length of the path traveled by an object.

Displacement

The shortest distance from the initial to the final position, including direction.

Average speed formula

Average speed can be calculated using v = distance ÷ time.

Acceleration formula

Can be expressed as a = (final velocity - initial velocity) ÷ time.

Final velocity formula

Can be calculated using v = u + at, where u is the initial velocity, a is acceleration, and t is time.