Name:____________________________ Period :___ Date:______
Acceleration on an Inclined Track
Kinematics: linear motion; constant acceleration, graphing
Qty
1
1
1
1
2
Equipment and Materials
LabQuest2/computer
Venier Motion Sensor
1.2 m PASCO Track
GOcar
Book
Purpose
The purpose of this activity is to investigate the relationship between position, velocity, and
acceleration for linear motion.
Background
Constant acceleration means a constant change of velocity. This could mean a constant change of
speed, a constant change of direction (such as uniform circular motion), or a combination.
Although constant velocity is straightforward, the graphical representation of constant
acceleration involves many fundamental concepts of kinematics. The slope of a plot of velocity
versus time for an object is the acceleration of the object. The ratio of the units along the vertical
and horizontal axes of a graph of velocity and time give the units for the object’s acceleration.
Whether the slope of velocity is positive or negative reveals the direction of the object’s
acceleration relative to the sensor.
Safety Precaution
● Follow all directions for using the equipment.
Procedure
Setup
1.
Put the range selection switch on the Motion Sensor to the ‘near’ (cart) setting.
● The Graph screen opens with a graphs of Position (m) versus Time (s),
Velocity(m/s) versus Time(s).
MAKE SURE YOU ZERO the sensor before each trial after you place the cart.
p. 19
PART 1
1. Place one box under the pods on one end of the track and place the sensor on that end.
2. Set your ipad to 1 graph and make the y axis “velocity”
3. Place the cart 15 cm away from the sensor.
4. Press collect, wait one second and let the cart roll.
5. Press stop when the cart reaches the end of the track.
6. Get the best fit linear line.
7. What is the name of the slope? ________Acceleration
8. Copy your graph here.
What is the value of the slope with correct units? _____________________
PART 2
9. Place 2 boxes under the pods on one end of the track and place the sensor on that end.
10. Set your ipad to 1 graph and make the y axis “velocity”
11. Place the cart 15 cm away from the sensor.
12. Press collect, wait one second and let the cart roll.
13. Press stop when the cart reaches the end of the track.
14. Get the best fit linear line.
15. Copy your graph here.
What is the value of the slope with correct units? ________________
PART 3
16. Place 3 boxes under the pods on one end of the track and place the sensor on that end.
17. Set your ipad to 1 graph and make the y axis “velocity”
18. Place the cart 15 cm away from the sensor.
19. Press collect, wait one second and let the cart roll.
20. Press stop when the cart reaches the end of the track.
21. Get the best fit linear line.
22. Copy your graph here.
What is the value of the slope with correct units? _____________________
Acceleration 1 box
Acceleration 2 boxes
Acceleration 3 boxes
PART 4
1.
Use 2 boxes to raise that end of the track so it is inclined at a small angle.
2.
Place the cart at the bottom of the track so the cart is facing the sensor. Aim the sensor so
its signal will reflect from the cart as the cart moves up and then back down the track.
Record Data
1.
Press Start
2.
Give the cart a firm push toward the Motion Sensor. (Don’t let the cart get closer than 15
cm to the sensor.) Continue collecting data until the cart has returned to the bottom of the
track. This may take a few practice pushes.
3.
4.
Press
to end data recording just as the cart reaches the end of the track.
Change the y axis to position and x axis is time. Draw 3 best fit lines. One for when it is
going towards the sensor, one for when it is stopped, and one for when it is going away
from the sensor. Copy your graph of data from the Motion Sensor for position versus time.
Fill in the chart below
Change the y axis to velocity. Draw 3 best fit lines. One for when it is going towards the
sensor, one for when it is stopped, and one for when it is going away from the sensor.
Copy your graph of data from the Motion Sensor for position versus time. Fill in the chart
below
5.
on the screen to begin measuring the sensor signal.
average velocity
average acceleration
up the track
stopped
down the track
6.
7.
8.
9.
10.
11.
12.
Change the number of graphs to 2. The top graph should be velocity vs time and the
bottom graph should be acceleration versus time.
Turn on interpolation.
Pick a specific time when the cart is moving up the track (for example at 1.1 seconds). Fill
in the chart below.
Pick a specific time when the cart is stopped on the track. Fill in the chart below.
Pick a specific time when the cart is moving down the track. Fill in the chart below.
COPY the graph from #10 with the interpolated line and box.
Find the percent difference by using the formula:
(top graph acceleration - bottom graph acceleration )
top graph acceleration *100%
time
chosen (s)
up the
track
stopped
down the
track
Velocity at
time
chosen
interpolate
d
slope
(from
chart
above)
acceleration
from slope
(top graph)
interploated
acceleration
(bottom
graph)
percent
difference
(tg-bg) /tg
Position vs. Time
Velocity vs time
Acceleration vs time
Questions (1-8 REFER TO PART 4 OF THE LAB)
1.
Describe the position versus time plot of the Graph screen. Curved or linear?
2.
Why does the distance begin at a maximum and decrease as the cart moves up the inclined
plane?
Becuase it is moving closer the sensor
3.
What kinematic equation describes this line?
4.
5.
Describe the velocity versus time plot. Curved or linear?
6.
What kinematic equation describes this line?
7.
Does the velocity begin in the positive or negative direction? (circle one) Why?
8.
Does the velocity end in the positive or negative direction? (circle one)Why?
9.
From your data would you say the acceleration was constant? Why or why not?
10.
The slope of a position vs time graph is called ______________________
IQ =
11.
The slope of a velocity vs. time graph is called _______________________