Here are the steps to solve this problem: a) Given: a = 0.21 m/s2, x = 280 m, vi = 0 m/s Use: vf = vi + at Substitute: vf = 0 + (0.21 m/s2)t Solve for vf: vf = 0.21t b) Given: a = 0.21 m/s2, x = 280 m Use: x = vit + (1/2)at2 Substitute: 280 = 0 + (1/2)(0.21 m/s2)t2 Solve for t: t = √(280/0.105) = 60 s

1. An airplane is flying 160 m/s at 76°. If the wind is
blowing 43.6 m/s at 136°, find the velocity the plane
will actually fly in.
(In other words…find the resultant of the following
vectors:)
G = 160 m/s @ 76°
Gx = 160 cos 76 = 38.7 m/s Gy = 160 sin 76 = 155 m/s
H = 43.6 m/s @ 136°
Hx = 43.6 cos 136 = -31.4 m/s Hy = 43.6 sin 136 = 30.3 m/s
xtot = 7.3 m/s ytot = 185.3 m/s
R = 7.3 + 185.3 = 185m / s
2 2
 185.3 
θ = tan 
−1
÷ = 87.7°
 7.3 

3. • Distance vs. Displacement
Distance
 the total path traveled. no direction (scalar)
d=A+B+C+D+E
C
B
D symbol for distance
E
A
x = resultant
R symbol for
displacement
(sometimes y)
Displacement
 from the very beginning to the very end.
includes direction so it is a vector

4. • Speed vs. Velocity
Speed (s or v)  distance divided by time
(no direction, scalar)
Velocity (v)  displacement divided by time (vector)
equation measured in
x meters m
v= = =
t second s

5. Heather and Matt walk with an average
velocity of 0.98 m/s eastward. If it takes
them 34 min to walk to the store, what is
their displacement?
Step 1: Draw a picture.
Step 2: Write out givens.
Givens:
v = 0.98 m/s 60 s
t = 34 min x = 2040 s
1min
Step 3: Convert units if necessary
Step 4: Write out equation. x = v t
Step 5: Substitute. x = (0.98)(2040)
Step 6: Solve.
x = 2000 m

7. • Acceleration
 change in velocity
How fast you change how fast you’re going
can change two ways: either change the symbol is “a”
magnitude or the direction.
unit is m/s2
3 equations,
with 4 5 total variables
variables 1
x = v t + at
i
2 x – displacement
2 vi – initial velocity
vf
v f = vi + at vf – final velocity
x a – acceleration
v f = vi + 2ax
2 2
t – time
t

8. A sailboat starts from rest and
accelerates at a rate of 0.21 m/s2 over
a distance of 280 m.
a. find the magnitude of b. find the time it takes
the boat’s final velocity the boat to travel
this distance.