P1003505

Uniform linear motion with thetimer 2-1

Physics Mechanics Dynamics & Motion

   
Difficulty level Group size Preparation time Execution time

easy 2 10 minutes 10 minutes

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Teacher information

Application

We find uniform rectilinear movements in technology

wherever something is moved uniformly from one place to
another, such as in conveyor belts: Here an object or
material moves in a constant direction at a constant speed,
which is specified by the belt.

By using two light barriers, the average speed of an object

between the two barriers can be determined. This
measurement method can be used in a slightly more
complex way, for example, to measure the average speed
of individual vehicles in road traffic over a longer section of
road.

Conveyor belt

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Other teacher information (1/2)

Prior The students should know how a light barrier works. In addition, initial experimental
experience in handling the Timer 2-1 is helpful.
knowledge
Notes on structure and implementation:

The speed of the measurement trolley can be quite dependent on the state of charge
of the batteries/accumulators of the measurement trolley.

Scientific The measuring carriage is driven by an electric motor and travels over the roadway at
a constant speed. Accordingly, the same shadowing times and thus speeds are always
principle measured with a constant speed setting of the measuring carriage.

Other teacher information (2/2)

Students should work out the properties of uniform rectilinear motion and
Learning experimentally learn speed as a ratio of s/t from the distance and time measurement
objective (distance-time diagram) of a carriage with drive. The students should recognise that the
speed within the measured distance is constant in this experiment.

Tasks 1. Measurement of the time taken by the experimental trolley to cover a given distance
using two light barriers at the beginning and end of the respective distance.

2. Calculation of the speed from the measured time between the interruption of one
and the other light barrier and the distance travelled.

3. Creation and discussion of the path-time diagram.

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Safety instructions

The general instructions for safe experimentation in science lessons apply to this
experiment.

Student Information

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Motivation

As you know, speed refers to the movement of an object

and implies how quickly or slowly it reaches one place
from another. In the case of vehicles on the road, the
speed is constantly changing. A typical example of a
constant speed movement is a conveyor belt, which is an
effective means of transporting all kinds of goods in many
areas.

They are used, for example, to convey rock or coal from

mines or in the logistics of large transport companies. The
transported material moves on the conveyor belt at a
constant speed. In this experiment you will learn how to
determine a uniform straight-line motion.
Conveyor belt

Tasks

1. Measure the time t required for the experimental trolley

to travel a certain distance s , with the help of two light
barriers at the beginning and end of the respective track.

2. Calculate the quotient s/t from the measured time t

between the interruption of the light barriers and the path
length s .

3. Present the determined regularities in graphical form.

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Equipment
Position Material Item No. Quantity
1 Car, motor driven 11061-00 1
2 Shutter plate for car, motor driven 11061-03 1
3 PHYWE Timer 2-1 13607-99 1
4 Light barrier, compact 11207-20 2
5 Adapter plate for Light barrier compact 11207-22 2
6 Connecting cord, 32 A, 1000 mm, red 07363-01 2
7 Connecting cord, 32 A, 1000 mm, yellow 07363-02 2
8 Connecting cord, 32 A, 1000 mm, blue 07363-04 2
9 Track, l 900 mm 11606-00 1

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Set-up (1/4)

Attach the shade screen to the test car and then place it at
one end on the flat roadway.

Fasten shut-off panel

Set-up (2/4)

Screw the adapter plates to the two forked light barriers in

such a way that they can be easily positioned next to the
roadway and the diaphragm on the carriage can pass
through the light barriers without bumping into them.

Connect light barrier with adapter

plates

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Set-up (3/4)

Connect both light barriers to the timing device.

Set the slide switch above the field labeled "Start" on the
timing device.

Connect forked light barrier to timer 2-1

Set-up (4/4)

Set the rotary switch to the third position from the left.
Then the device displays the time that elapsed between the
interruption of the first and the second light barrier. In this
experiment, this is the time it took the car to travel the
distance between the two light barriers.

Set up the light barriers at a distance of 10 cm from each

other. The starter light barrier must be the one that is
closer to the measuring carriage. In addition, the starter
photocell should be at least a few centimetres away from
the measuring trolley. To measure the distance between
the light barriers, you can orientate yourself on the centre
seams of the light barriers and use the measuring tape on
Adjusting the device the track.

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Procedure (1/3)

Set the speed slider on the trolley to the lowest speed

(left stop).

Press the "Reset"-button on timer 2-1.

Adjusting the speed on the trolley

Procedure (2/3)

Now start the car with the direction switch in the

desired direction.

After the cover on the measuring carriage has passed

both light barriers, the timer 2-1 displays the measured
time.

Note the measured value in the report in Table 1.

Starting the car

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Procedure (3/3)

Repeat the experiment for the distances s of 20 cm, 30

cm, 50 cm and 60 cm. Also note these measurements in
the report in Table 1.

Now set the speed controller on the measuring car

approximately to the middle position.

Measure the times taken by the trolley for the

measurement distances of 10 cm, 20 cm, 30 cm, 50 cm
and 60 cm.

Note these readings in Table 1.

Starting the car

Report

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Table 1

Enter the measured values for the travel times at the low speed (t1 [s]) and at the average speed (t2 [s])
in the respective table. Then calculate from the routes s and the corresponding travel times t the speed
as quotients v = s/t and enter them as well.

s [cm] s =t [10cm: ts[cm

= /10cm: v_ s =t 10cm: t
v2s[cm
= /10cm: v_
1 s] v1 s] s [cm] 2 [s] s]

s = 20cm: ts = 20cm: v_ s = 20cm: ts = 20cm: v_

10 10
s = 30cm: ts = 30cm: v_ s = 30cm: ts = 30cm: v_
20 20

30 s = 50cm: ts = 50cm: v_ 30 s = 50cm: ts = 50cm: v_

50 s = 60cm: ts = 60cm: v_ 50 s = 60cm: ts = 60cm: v_

60 60

Task 1

Now take a sheet of paper and create a diagram on it. In

this diagram, you represent the distance traveled s (yaxis)
as a function of time t (x axis).

Draw the curves for the low and medium speed.

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Task 2

What is the approximate shape of the curve?

 Linear Function.

 Quadratic function.

 Constant function.

 Check

Task 3

Which of the statements is true for the path-time diagram found?

 The way s is the time t proportional.

 The path travelled s grows square with time t .

 There is no connection between path s and time t .

 Check

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Task 4

In Table 1 you have calculated the speed as the respective ratio v = s/t.

Which statements are true for this experiment?

 The speed depends on the travel time.

 The greater the speed, the less time is needed to cover the same distance.

 The greater the travel distance, the greater the speed.

 The speed within a trip can be considered constant.

 Check

Table 2

This table refers to the partial test with the average speed of the measuring trolley.

Support for the legs listed in the table Δs enter the required times that the measuring carriage needs for
these sections in the second column.
Δs [cm] delta
Δt [s] s =v =
delta
Δs/Δst [cm
= 20cm
/ s] - 1
To do this, you look up the travel times in
Table 1 that the measuring wagon took to delta s = delta s = 30cm - 2
reach the respective route and calculate the 20 - 10 = 10
time difference accordingly. Δt. delta s = delta s = 50cm - 3
30 - 20 = 10
Indicate the speed of the section in the third delta s = delta s = 60cm - 5
50 - 30 = 20
column (v = Δs/Δt).
60 - 50 = 10

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Task 5

What is the relationship between the diagram sections (for the measurement car at the mean
speed in the diagram) and the section speeds calculated in Table 2?

 The diagrams have the same result.

 The diagrams have different results.

 There is no analogy whatever.

 Check

Task 6

Which statement is true?

 The term "uniform" has nothing to do with line section speeds.

 The line section speeds differ greatly, which is why the movement is called uniform.

 The line segment velocities are (approximately) equal: There is a uniform movement.

 Check

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Slide Score / Total

Slide 20: Waveform 0/1

Slide 21: Path-time diagram (1) 0/1
Slide 22: Path-time diagram (2) 0/2
Slide 24: Correlation of the test results 0/1
Slide 25: Line section speed 0/1

Total 0/ 6

 Solutions  Repeat  Export text

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