Ticker Timer PDF

Preview

Summary

Experiment about usage of ticker timer...

Description

PRAC: TICKER TIMER Linear Motion | Aim: How does a ticker tape timer record the motion of an object? Equipment: - Ticker Timer - Tape - Transformer - Electrical Leads Risk Assessment: Identify

Rating

Electrocution/Shock

Med

Hitting Something When Pulling Tape Finger/Skin Getting Caught Underneath the Hammer

Low Med

Minimisation Use of transformer, not touching the wires while in power, switching the power off when not in use. Ensure no-one/nothing is behind you before pulling the tape. Keep your finger well outside the plastic guide.

Procedure (12-15 Steps): 1) Set up the equipment as below:

2) Take an electrical lead and connect it to the AC terminal of the transformer to the ticker tape timer.

3) Take a second electrical lead and connect it to the other AC terminal to the other terminal on the ticker tape timer. 4) Turn on the transformer to 8 or 10 volts. 5) Take a 30/40cm strip of tape. 6) Feed the tape through the first plastic guide. 7) Make sure under the carbon paper and under the hammer of the ticker tape timer. 8) Feed the tape through the second plastic guide. 9) Make sure that there is a little strip of tape outside the second plastic guide, to allow you to pull the strip. 10) When ready, tell your partner to turn on the power. 11) When the power starts, pull the tape through, in a relatively fast pace. 12) Turn the power off when paper it fully fed through. 13) If the dots are faded or weak, turn the carbon paper and retry. 14) Cut the paper in their different speeds (fast, medium and slow). 15) Record and analyse your findings.

Results:

No. of time 2

Total Time:

Motions

Distance (cm)

spaces between dots

Slow

3.4

9

Medium

7.7

8

Fast

13.2

9

No. of time spaces x time in one space 9 x 0.02 = 0.18 8 x 0.02 = 0.16 9 x 0.02 = 0.18

Velocity

3.4 ÷ 0.18 = 18.88* cm/s 7.7 ÷ 0.16 = 48.125 cm/s 13.2 ÷ 0.18 = 73.33* cm/s

* means repeater

In my set of results, the tape’s motion starts off extremely slow at first, but accelerates into a medium pace. The tape then quickly accelerates into a fast pace, and continues at this pace until the end. Analysis:

Analysis (Responses): a) Explain why can we say that the tape X shows constant speed? State the value. Looking at Tape X, we can see that the gaps between the dots are very similar, roughly 1.4cm per gap. To calculate the velocity, we use the formula of velocity = distance/time. In this case, the total distance of the gaps is 13.3cm which is 0.133 3

metres. Every gap is 0.02 seconds, and there are a total of 9 gaps, meaning the total time is 0.18 seconds. Using the formula becomes, V= 0.133cm/0.18sec. Therefore the total velocity is

0.738 metres per second.

b) Find the average speed of the block between 5th and 6th dots in Y? The average speed formula is speed = distance/time. The distance between the two dots is 3.7 cm equating to 0.037 metres, and the time distance is 0.02 seconds. Therefore, the average speed is 0.037/0.02, which results in 1.85 metres per second. c) Measure the distances between dots for tape Z. By how much do they differ?

Determine the average speed for each space on the tape Z. Use these values to calculate the acceleration of the block by using the definition of acceleration. Space 1 | Distance: 2mm

Speed: 0.1 metres per second

Space 2 | Distance: 4mm

Speed: 0.2 metres per second

Space 3 | Distance: 20mm

Speed: 1 metre per second

Space 4 | Distance: 87mm

Speed: 4.35 metres per second

The formula for average acceleration is (final velocity – initial velocity) / time. The time for the tape Z is 0.02 seconds times 4 gaps, resulting in 0.08 seconds. For tape Z, the acceleration is (4.35 – 0.1) / 0.08 which is 53.125 metres per second squared. d) Mark the dots on a blank tape for a body that accelerates at 5mms-2.

e) Explain how the spacing in the tapes above would differ if the timer had a

frequency of 25Hz. Since this ticker timer is set of a frequency of 50Hz, it marks a dot twice the speed of 25Hz. If the timer was set in 25Hz, the spaces between the dots would be twice as long as they were in the 50Hz timer.

4

f) State a major source of error in this experiment. When the tape goes through the hammer of the ticker timer, there may be a little drag within the tape, resulting in some smudging and in consistencies within the dots and the results of the tape. This difference is large enough to alter the accuracy of the experiment. Conclusion: Kinematics is the branch of physics that relates to the motion of objects. Linear motion, also known as rectilinear motion, is the motion within a straight line. A ticker timer is a device that is able to record the motion of an object by placing dots every 0.02 on a piece of tape while in motion, resulting in a constant stream of dots. This stream of dots reveals the objects/tape’s motion by showing the difference of space between the dots. A large gap in the dots means the object is moving faster, while a smaller gap means that the object is moving slower. The acceleration or deceleration of an object can also be found by a ticker tape timer, by comparing the constant increase or decrease of the distance in the gaps.

Extension: Police Radar Gun

Diagram:

5

A police radar gun is a device used by the police force to measure a vehicle’s speed. A police radar gun is consisted of two main parts – a radio transmitter and a radio receiver. The radio transmitter emits an electrical current at different voltages, generating electromagnetic electricity. This electromagnetic electricity travels through the air in a form of electromagnetic waves, until it hits the targeted object/vehicle. When the waves hit the object/vehicle, the waves are reflected and head back towards the radar gun. The reflected electromagnetic waves are picked up by the radio receiver, through an antenna, and converts the waves back into an electrical current. The police radar gun is able to measure the object’s speed, by measuring the Doppler shift in the signal. The Doppler shift is the change in frequency or wavelength of a wave in relation to the observer. By measuring the Doppler shift within the radar gun and vehicle, the radar gun is able to quickly calculate how fast a vehicle is travelling and how quickly it is moving away or towards the gun. By using radar guns, the police are able to track a vehicle’s speed and check if a vehicle is obeying the road rules by going under the speed limit. The police have been using this form of technology for over 50 years, and has been able to catch many drivers speeding and stop them.

References: Web Address:

6

Name of Website:

Author:

Date Accessed

https://www.neltronics.com.au/howdoes-a-speed-camera-or-radar-gun-work/ http://theconversation.com/explainerthe-doppler-effect-7475 https://www.azosensors.com/article.aspx ?ArticleID=218 https://www.thomasnet.com/articles/instr uments-controls/how-radar-detectorswork https://sciencestruck.com/radar-gunshow-they-work

7

Neltronics

Unknown

The Conversation Azo Sensors

Gillian Isoardi Unknown

Thomas Net

Unknown

Science Struck

Unknown

21 February 2019 22 February 2019 22 February 2019 23 February 2019 23 February 2019...