Unit 3

• Force - a push or pull one thing exerts on another

  • examples of force - gravity, magnetism, air, friction

• Friction - the resistance that one surface or object encounters when moving over another

• F_net - the sum of all forces that act on an object

• inertia - the momentum that is resistant to change in an object

• equilibrium - where all forces acting on an object are balanced, resulting in no net force

• mass vs. weight - mass is determined by the amount of matter an object has, and weight is determined by the amount of matter and the force of gravity acting upon it

Formulas

• 1 Newton = 1 kg x 1 m/s²

• First Law of Motion - F_net = 0

• Second Law of Motion - F_net= m x ā

• weight of an object - F_g = mg

Newton’s Laws of Motion

1. if f_net=0, then the object is at rest or moving with a constant velocity and is at equilibrium

2. net force and acceleration are directly related

3. -

Acceleration

• acceleration is positive at all times during calculations

• when acceleration is pointing downwards - F_r < F_g

• when acceleration is pointing downwards - F_r > F_g

Normal Force

• Normal force - a force exerted by the surface an object is on that is perpendicular to the surface

• Normal force and the force of gravity cancel each other

Movement at an Incline

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