Guide questions What is friction? What are the types of friction? How do they differ from each other? How do we describe friction?
Guide questions What is air resistance? How does a body attain terminal velocity? How do we increase/decrease friction?
Key terms Friction force (Ff) – a force that tends to oppose motion Coefficient of friction (µ) – the ratio of the friction force to the normal force
Key terms Static friction – the type of friction that exists between the contact surfaces of two bodies at rest Kinetic friction – the force that opposes sliding motion
Key terms Rolling friction – the force that opposes rolling motion Normal force (Fn) – the force pressing two contact surfaces together
Key terms Air resistance – the friction between air and a body moving through it Terminal velocity – the velocity acquired by a freely falling body when its weight equals the upward force exerted by air