96 Vector Components

1
9/6 Vector Components

• Text sections and 1.6-8
• HW 9/6 2-D Vector Components due Wednesday 9/11
• On web or in 213 Witmer for copying

2
Concepts so far-
3
Problem
An object goes from a velocity of 15 m/s right to
6 m/s right in 3 seconds. Find the acceleration,
both its size (magnitude) and its direction,
(left or right). How do the directions of the
velocity and acceleration compare? What is the
object doing during these 3 seconds? How far did
the object travel during these three seconds?
Hint What is the average velocity? What will
the objects velocity be in three more seconds if
the acceleration stays the same?
4
Problem
A bullet exits a rifle at 85m/s. The barrel is
0.75m long. What is the acceleration of the
bullet?
Dont use text equations, just the relationships
between displacement, time, velocity and
acceleration
5
Find the Displacement
v (m/s)
How far did the object go in 9 seconds?
10
What is the average velocity?
7 m/s
t (s)
10
Displacement 63 m
There are 31.5 shaded squares each representing 2
m of displacement. 2 x 31.5 63
6
Find the Displacement
v (m/s)
At what time is the object back where it started
from?
10s
10
What is its velocity at this time?
-8m/s
If it returns to its starting point it must turn
around. At what time does it do that?
t (s)
10
6s
-10
What is the displacement from 2s to 13s?
How many meters were put on the odometer from 2s
to 13s?
7
Finding x and y Components
vx ?
?
? 21 below horizontal
vy ?
v 3.8 m/s
Opposite from ?, use SinAdjacent to ?, use Cosine
vy 3.8 Sin 21 1.4m/s
vx 3.8 Cos 21 3.5m/s
Make sure your calculator is set to degrees!
8
Finding x and y Components
vx ?
vx 15 Sin 35 8.6m/s
v 15 m/s
vy 15 Cos 35 12.3m/s
vy ?
? 35