CHOOSING KINEMATICS EQUATIONS

#1: v = v0 + at

#2: Δx = (v0)t + (1/2)a(t^2)

#3: Δx = ((v + v0)/2)t

#4: v^2 = (v0)^2 + 2aΔx

FIRST ask yourself, what are Δx, v0, v, a, and t

(1)________________________________________

Δx = we do not know

v0 = rest, 0 m/s

v = 80.0 km/h

a = 1.45 m/s/s

t = ASKS US TO FIND

-we don't know Δx and it does not ask for it, so we can rule out equations 2, 3, and 4, leaving #1

v = v0 + at

t = (v - v0)/a

(2)________________________________________

Δx = ASKS US TO FIND

v0 = rest, 0 m/s

v = ASKS US TO FIND

a = 2.40 m/s/s

t = 12.0 s

-for the first part, we need Δx, and we know that we do not have the final velocity either, so we can rule out all equations but #2

Δx = (v0)t + (1/2)a(t^2)

-after we find Δx, we can plug it back into really any of the equations, but if we didn't want to find Δx first, we could use equation #1

v = v0 + at CHOOSING KINEMATICS EQUATIONS

#1: v = v0 + at

#2: Δx = (v0)t + (1/2)a(t^2)

#3: Δx = ((v + v0)/2)t

#4: v^2 = (v0)^2 + 2aΔx

FIRST ask yourself, what are Δx, v0, v, a, and t

What do we know?

Δx = yes (41 m)

v0 = NOT GIVEN, ASKED TO FIND

v = yes (35 m/s)

a = NOT GIVEN

t = yes (2.3 s)

-since we do not have a and it does not ask for it, we can rule out equations 1, 2, and 4, leaving #3

Δx = ((v + v0)/2)t 3rd EditionRobert F. Blitzer5,343 solutions

6th EditionMichael Sullivan, Michael Sullivan III7,232 solutions

5th EditionDavid C. Lay, Judi J. McDonald, Steven R. Lay2,030 solutions

9th EditionArthur David Snider, Edward B. Saff, R. Kent Nagle2,119 solutions