PhysicsCode 5054
Balanced and unbalanced forces
What this topic asks you to be able to do
- Identify the various kinds of force and use them, including contact force, friction, drag, air resistance, weight (gravitational force), thrust (driving force), tension (elastic force), magnetic force and electrostatic force
- Identify the forces that act upon a body, and sketch free-body diagram(s) showing them
- State Newton’s first law: unless a resultant force acts on it, an object stays at rest or keeps moving at constant speed in a straight line
- State that a force can change an object's velocity, either by changing the direction in which it moves or by changing its speed
- Determine the resultant when several forces (two or more) act along one straight line
- Recall resultant force = mass × acceleration and use this equation in calculations
- State Newton’s third law: whenever object A applies a force to object B, object B applies a force to object A that is equal in size and opposite in direction
- Know that Newton’s third law deals with forces that come in pairs, where both forces are the same type but act on different objects