CH 2.5-2.8 Flashcards

Air Resistance

causes lighter objects to fall slower than heavier ones of the same size, opposes motion of object through air

Friction

opposes motion between objects  when they interact

Free-Fall

when an object is falling without air resistance or friction

Acceleration Due to Gravity

acceleration of free-falling objects

Describe how you alter some common variables if the initial time/position/velocity is 0

t₀/x₀/v₀ = 0, then t = final time, x = final position, v = final velocity and

Δt = t, Δx = x, Δv = v

What can you assume for some motions if acceleration is constant?

can assume that constant acceleration = average acceleration

What is the equation for average velocity?

V̄ = Δx/Δt = (x – x₀)/t

What is the equation for average velocity if there is constant acceleration?

V̄ = (v₀ + v)/2

What is the equation to find final position using constant velocity?

x = x₀ + V̄t

When acceleration is constant, what can you assume v is?

it is the simple average of initial and final velocities

Give an example of finding average velocity with a constant acceleration

steadily increase velocity from 30 to 60km/hr, average velocity is then 45km/hr

V̄ = v₀ + v/2 = 30km/hr + 60km/hr / 2 = 45km/hr

What does final velocity depend on in terms of acceleration?

depends on how large acceleration is and how long it lasts

Describe the relationship between acceleration and velocity in terms of their signs

if acceleration = 0, final velocity = initial velocity

if acceleration is negative then final velocity < initial velocity