Science - Physics - Mechanics - 2 Forces
(P0999600)
2.9 Resolution of forces on an inclined plane
Experiment by: 1.3 determination of the mass of solid and liquid
bodies
Printed: Jan 10, 2011 10:59:18 AM
interTESS (Version 10.03 B132, Export 1678)
Task
Task
What forces pull a car downhill?
There is a car on an inclined plane.
You will determine the downhill force which acts parallel to the plane and the normal force which
acts perpendicular.
Use the space below for your own notes.
Logged in as a teacher you will find a button below for additional information.
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Material
Material
Material from "TESS-Mechanics ME1" (Order No. 13271.88) and "TESS-Mechanics
ME2" (Order No. 13272.88)
Position No.
Material
Order No. Quantity
1
Support base, variable
02001.00
1
2
Support rod, stainless steel 18/8, l = 600 mm, d = 10
mm
02037.00
1
2
Support rod, stainless steel 18/8, l = 250 mm,
d = 10 mm
02031.00
1
2
Support rod with hole, stainless steel, 100 mm
02036.01
1
3
Bosshead
02043.00
2
4
Spring balance, transparent, 1 N
03065.02
1
4
Spring balance, transparent, 2 N
03065.03
1
5
Spring balance holder for transparent Spring balances
03065.20
1
6
Holding pin
03949.00
1
7
Slotted weight, black coloured, 50 g
02206.01
2
8
Measuring tape, l = 2 m
09936.00
1
9
Fish line, in reel, d = 0.7 mm, 20 m
02089.00
10
Car for measurings and experiments
11060.00
1
11
Track 1, l = 500 mm
11302.00
1
Additional
Material
Scissors
1
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Material required for the experiment
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Setup
Setup
Set up a stand with the support base (Fig. 1), the 600 mm support rod (Fig. 2) and the two
bossheads (Fig. 3).
Fig. 1
Fig. 2
Fig. 3
Insert the spring balance holder into the short support rod (Fig. 4).
Clamp the short support rod into the upper bosshead and the 250 mm support rod into the lower
bosshead (Fig. 5).
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Fig. 4
Fig. 5
Hang the track into the 250 mm support rod and fix the 1 N spring balance into the spring balance
holder (Fig. 6). Make sure that the spring balance is centered above the upper end of the track.
Fig. 6
Attach the car to the 1 N spring balance and insert the holding pin into the hole in the upper
surface of the car (Fig. 7).
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Fig. 7
Attach the 2 N spring balance to the holding pin with a short piece of fish line.
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Action
Action
First, determine the weight (force) Fg of the car alone (Fig. 8); then with one additional 50 g mass
(piece) and finally with two additional 50 g masses (Fig. 9). Record the measured values in Tables 1
and 2 on the Results page.
Fig. 8
Fig. 9
Set the height of the track h to 20 cm, measure b and l with the measuring tape (Fig. 10) and
record the values in Table 1 on the Results page.
Fig. 10
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• Lift the car without an additional mass (piece) with the 2 N spring balance until the wheels
just do not touch the track. Make sure that you are always pulling in a perpendicular direction
to the track (Fig. 11).
• Read both spring balances and record the values for Fh and Fn in Table 1 on the Results page.
• Repeat the same measurements with the car loaded with mass pieces of ma = 50 g and then
with ma = 100 g (Fig. 12).
• Record all the values in Table 1 on the Results page.
Fig. 11
Fig. 12
Set the height to 30 cm. Remeasure b with the measuring tape and record this value as well as
the value for l in Table 2 on the Results page.
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• First, measure Fh and Fn with the unloaded car, then with an additional mass of 50 g and
finally with 100 g.
• Record all the values in Table 2 on the Results page.
In order to disassemble the support base you should press the yellow buttons (Fig. 13).
Fig. 13
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Results
Results
Table 1
h = 20 cm
l = nnnnnnnnnn cm; b = nnnnnnnnnn cm
ma in g
Fg in N
Fn in N
Fh in N
h / l = nnnnnnnnnn ; b / l = nnnnnnnnnn
Fh / Fg
Fn / Fg
0
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
50
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
100
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
Table 2
h = 30 cm
l = nnnnnnnnnn cm; b = nnnnnnnnnn cm
ma in g
Fg in N
Fn in N
Fh in N
h / l = nnnnnnnnnn ; b / l = nnnnnnnnnn
Fh / Fg
Fn / Fg
0
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
50
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
100
nnnnnnnnnn nnnnnnnnnn nnnnnnnnnn
nnnnnnnnnn
nnnnnnnnnn
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Evaluation
Evaluation
Question 1:
Form the quotients Fh / Fg and h / l in Tables 1 and 2 on the Results page and compare them with
each other. What do you observe?
Question 2:
Form the quotients Fn / Fg and b / l in Tables 1 and 2 on the Results page and compare them with
each other. What do you observe?
Question 3:
Draw the parallelogram of forces for two pairs of forces (Fh, Fn) for different masses and heights:
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Question 4:
Which force must you exert when you pull a car up a hill?
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Additional Tasks
Additional Task
Which trigonometric formulae describe the following quotients?
Fn / Fg = b / l =
sin α
cos α
2 sin α
cos 2α
Fh / Fg = h / l =
sin α
cos α
2 sin α
cos 2α
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