Forces and Motion Study Guide

Forces and Motion

• This study guide helps review and organize forces and motion material.
• Review notes, readings, and assignments.
• A completed study guide is needed for test corrections.

Learning Objectives

• Define force and the SI unit

  • Force is a push or pull.
  • The SI unit of force is the Newton (N).

• Explain why force is a vector quantity:

  • Forces have both magnitude and direction.
  • Scalars (like mass, length) only have magnitude.

• Give examples of contact and non-contact forces

  • Contact forces require physical touch (friction, normal force).
  • Non-contact forces act at a distance (gravity, magnetism, electric force).

• What is gravity?

  • Gravity is a force of attraction between objects with mass.

• Relationship between gravitational force, mass and distance

  • Gravitational force is strongest between objects with large masses.
  • Gravitational force decreases with increasing distance between objects.

Additional Concepts

• Distinguish between mass and weight:

  • Mass is the amount of matter in an object (measured in kilograms).
  • Weight is the force of gravity on an object (measured in Newtons).

• What causes friction and factors affecting it?:

  • Friction opposes motion between surfaces in contact.
  • Factors influencing friction include surface roughness and the force pressing the surfaces together.

• Identify balanced and unbalanced forces:

  • Balanced forces have equal magnitudes and opposite directions, resulting in no change in motion.
  • Unbalanced forces have unequal magnitudes, causing a change in motion (acceleration).

• Relationship between speed, distance and time:

  • Speed is the rate of change of distance over time (distance/time).

• Compare speed, velocity, and acceleration:

  • Velocity includes both speed and direction (a vector quantity).
  • Acceleration is the rate of change of velocity over time.

• Calculate speed and velocity:

  • Speed = distance / time
  • Velocity = displacement / time

• Interpret distance-time graphs

  • The slope of a distance-time graph represents speed.
  • A horizontal line indicates no motion. A positive slope indicates that the speed is constant and motion exists.

• Explain and calculate acceleration

  • Acceleration is the rate of change of velocity (velocity/time)
  • Positive and negative acceleration involve changes in direction and magnitude of velocity.