Science 10
Mr. Bellman
Physics UNIT
Ch 9 Acceleration
Notes and workbook wkst p167
NAME____________________
Date______________Bk_____
(16 )
Notes: The three equations used involving change in velocity ( ΔV ), initial velocity ( ΔV i ), and final velocity ( ΔVf ) are:
ΔV = Vf – Vi
Vi = Vf – ΔV
Vf = Vi + ΔV
(given on data booklet)
Notes: If + V, the object is moving in the positive direction, forward, up, north, east, etc.
If – V, the object is moving in the negative direction, backwards, down, south, west, etc.
Notes: Signs of velocity, change in velocity, and acceleration describe the motion of the object and if it is speeding up or slowing
down.
Initial velocity
+ 6 m/s
Final velocity
+ 10 m/s
Change in velocity (ΔV)
+ 4 m/s
Acceleration
+
+ 9 m/s
+ 4 m/s
- 5 m/s
-
- 2 m/s
- 8 m/s
- 6 m/s
-
- 8 m/s
- 1 m/s
+ 7 m/s
+
+ 3 m/s
+ 3 m/s
0 m/s
0
- 4 m/s
- 4 m/s
0 m/s
0
0 m/s
0 m/s
0 m/s
0
Description of motion
Object speeding up while moving forward
ACCELERATING FORWARD
Object slowing down while moving forward
DECELERATING WHILE MOVING FORWARD
Object speeding up while moving backward
ACCELERATING BACKWARDS
Object is slowing down while moving backward
DECELERATING WHILE MOVING BACKWARD
Object moving forward at constant speed
Not accelerating or decelerating, UNIFORM MOTION
Object moving backward at a constant speed
Not accelerating or decelerating, UNIFORM MOTION
Object not moving, object at rest
Not accelerating or decelerating, UNIFORM MOTION
Notes:
If the object’s acceleration is the same sign as the direction the object is moving, the object is speeding up in that direction.
If the object’s acceleration is opposite the sign of the object’s direction of travel, the object is slowing down in that direction.
If the object’s acceleration is zero, the object is moving at a constant speed in whatever direction the object is moving.
Workbook page 167 (modified slightly)
The following table is data
collected from a bus moving
north at 10 second intervals.
1. Sketch a graph of velocity
vs time. (Put time on x axis)
Time (s)
0
10
20
30
40
50
Velocity (m/s) [N]
0
15
28
28
22
12
2. Determine the ΔV for each time interval and describe the motion of the bus in terms of direction of motion and acceleration.
EQUATION USED
WORK
ΔV
DESCRIBE THE MOTION OF THE BUS
a. 0 to 10 s
b. 10 to 20 s
c. 20 to 30 s
d. 30 to 40 s
e. 40 to 50 s
ΔV = Vf – Vi
Answers to Q 2. a. + 15 m/s speeding up moving [N], b. + 13 m/s speeding moving [N] just not as fast as before
c. 0 m/s moving at a constant speed [N], d. – 6 m/ slowing down moving [N], e. – 10 m/s slowing down even more moving [N]
3. Calculate the missing quantity using the equations from the data booklet or at the beginning of this worksheet. Include the
equation used, the work, the answer, a description of the object’s motion (direction of motion, speeding up or slowing down or
constant speed or not moving), and whether the motion is uniform or non-uniform. Assume + is forward motion.
equation used
work
answer
description of object’s motion
a. Vi = + 5 m/s
Vf = + 14 m/s
ΔV = ?
b. Vi = - 6 m/s
Vf = - 10 m/s
ΔV = ?
c. Vi = + 20 m/s
Vf = + 7 m/s
ΔV = ?
d. Vi = - 15 m/s
Vf = - 8 m/s
ΔV = ?
e. Vi = + 4 m/s
Vf = + 4 m/s
ΔV = ?
f. Vi = - 18 m/s
Vf = ?
ΔV = 0 m/s
g. Vi = ?
Vf = 0 m/s
ΔV = 0 m/s
h. Vi = + 11 m/s
Vf = ?
ΔV = - 11 m/s
i. Vi = ?
Vf = - 22 m/s
ΔV = - 10 m/s
j. Vi = - 3 m/s
Vf = + 22 m/s
ΔV = ?
ANSWERS:
a. + 9 m/s speeding up moving forward
b. – 4 m/s speeding up moving backward
c. – 13 m/s slowing down moving forward
d. + 7 m/s slowing down moving backward
e. 0 m/s moving at a constant speed forward
f. – 18 m/s moving backward at a constant speed
g. 0 m/s object not moving
h. 0 m/s moving forward slowing down to a stop
i. – 12 m/s speeding up moving backward
j. + 25 m/s object moving backwards slowing down to a stop, then
accelerated forward. (Tricky)