Download Lab: Constant Acceleration of a Fan Cart

Lab: Constant Acceleration of a Fan Cart
Fan Cart Lab
Name ________________________________
Partners _______________________________________________________
Introduction:
The purpose of this lab activity is to study Newton’s Second and Third Laws via the
acceleration of a cart with a mounted fan or propeller.
Background:
When a fan or propeller is attached to a body capable of motion it causes the body to
accelerate by Newton’s 2nd and 3rd Laws. The acceleration is equal to the Net Force on the
body divided by its total mass.
Equipment List:
Pasco 750 interface, motion sensor, mountable fan, dynamics cart, 1.2 m track, Pasco
Capstone software, Excel software
Fan Cart
Partial Assembly
Safety Reminder: Keep hands clear of fan blades. Catch the fan cart before the cart gets to the end of
the track. Do not stick anything into the fan blade Housing!
Procedures: (Make sure to turn on the 750 interface box before you start the data studio software.)
NOTE: Make all plots with Excel.
A. Set up the 750 interface and G:\High School\Instructional\Physics Brandstaedter\fan_cart
B. Connect the yellow plug of motion sensor to port1 and black to port2 of the 750 interface.
C. Measure the mass in kilograms of the
a. Combined Fan-Cart:
_______________________ kilograms (Make sure the batteries and metal
cylinder begin in the cart, but without the rectangular weights.)
D. Place the track on the lab table and place the fan cart on the track. If the cart rolls forward or backward then
your track is in need of leveling. There are leveling legs holding up the track. Adjust the legs until the track
is level and the cart stays stationary wherever it is placed on the track.
E. Once your Capstone software/Interface 750 is ready to run then you turn on the fan, but hold the fan-cart in
place until you can coordinate with your partners the time to start the run and let go of the fan cart. **
Catch the cart before it hits the end of the track or you will damage it. **
F. From the slope of the speed vs. time graph determine the acceleration of the fan-cart and record it here:
agraph = _______________m/sec2.
G. Copy the graph of speed vs. time of the combined fan cart below.
H. Using Newton’s 2nd Law, the total mass of the fan cart and its acceleration, solve for the Net Force produced
by the fan.
FNET = mfan-cart(agraph)
Record FNET here: ______________Newtons
I. Repeat procedures A through G, but this time remove the two cylinder weights from your fan. Measure the
mass of these two weights and record them here:
Record 2 cylinders here: ______________Kilograms
New Fan cart mass (minus the 2 cylinders): ____________ Kilograms
J. From the new speed vs. time graph determine the acceleration of the fan-cart minus the 2m.
a'graph = _______________m/sec2
K. Copy the graph of speed vs. time of the combined fan cart below.
L. Using Newton’s 2nd Law, the total mass (m”fan-cart) of the fan cart without the 2m and its acceleration from
procedure H, solve for the new Net Force produced by the fan.
F’NET = m’fan-cart(a’graph)
‘
Record F’NET here: ______________Newtons
M. Replace the two silver gray weights from your fan and add the 2 rectangular weights underneath the fan.
Measure the new mass.
Record mass here: ______________Kilograms
N. Using the FNET produced by the fan and new mass of the cart, calculate the acceleration using
FNET = m”fan-cart(a”calc)
a”calc = _______________m/sec2
O. Repeat procedures A through G, with the new fan cart. From the slope of the speed vs. time graph
determine the acceleration of the fan-cart and record it here:
a”graph = _______________m/sec2.
P. Copy the graph of speed vs. time of the combined fan cart below.
Q. Calculate the percent difference between a”calc and a”graph
Acceleration vs mass Plot:
Make a plot (in Excel or by hand) of acceleration vs mass.
Report:
One report per person
Write your name and partners
Print a of the velocity vs time plot for only the first trial. Be sure the slope is displayed.
Attach sheets in the following order:
Data sheet
v vs t plot
a vs m plot
questions
Questions (Answer all questions on a separate sheet)
1. What is the shape of the velocity vs. time graph? What does this mean about the fan cart?
2. What is should the relationship between mass and acceleration be when the force is held constant?
3. What was the effect on acceleration occurred when the rectangular masses were added to the cart?
4. A snow sled is being pushed on silky smooth snow by a boy with a force of Fpush = 252 N, East. The sled
has his sister sitting in it. The mass of the sled is mS = 20.2 kg and the girl’s mass is mG = 33.2 kg.
(a) Sketch the girl on the sled on the snow and draw and label all the force arrows acting on the combined
girl-sled system.
(b) Determine the acceleration of the girl-sled system.
(c) If the sled is pushed for 10.0 seconds, how fast us it moving at that moment?
(d) How far did it move in those 10.0 seconds?
(e) If the snow was rough and crystalline that friction developed and the friction force was exactly 0.5 of the
Fpush (push force), what would be the acceleration of the girl-sled system?