1 Technology-Rich Transportation Engineering ExperiencesLouisiana Tech University SPTC Technology-Rich Transportation Engineering Experiences Velocity Vectors
2 Activity 1 Background Practice using technology Collect dataSPTC Activity 1 Background Practice using technology Collect data -> Lunch Analyze data
3 Learning Objectives/StandardsSPTC Learning Objectives/Standards CCSS.Math.Content.HSN.VM.A.1 (+) Recognize vector quantities as having both magnitude and direction. Represent vector quantities by directed line segments, and use appropriate symbols for vectors and their magnitudes (e.g., v, |v|, ||v||, v). CCSS.Math.Content.HSN.VM.A.3 (+) Solve problems involving velocity and other quantities that can be represented by vectors. CCSS.Math.Content.HSG.SRT.C.8 Use trigonometric ratios and the Pythagorean Theorem to solve right triangles in applied problems. CCSS.Math.Content.HSG.SRT.D.11 (+) Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and non-right triangles (e.g., surveying problems, resultant forces).
4 SPTC Problem Statement Transportation engineers often need to measure the speed with which people drive on a particular segment of road. Radar guns can be used for this purpose, but they only measure the speed at which a car approaches the gun. How can a transportation engineer safely determine the true speed?
5 SPTC Background Radar uses the change in frequency of the radio pulse that bounces back (Doppler effect). Brain, Marshall. "How Radar Works" 01 April 2000. HowStuffWorks.com.
6 You will need Radar guns Measuring tape A non-busy roadSPTC You will need Radar guns Measuring tape A non-busy road Sidewalk chalk or flag markers A driver and vehicle
7 Get your radar gun readySPTC Get your radar gun ready Load batteries Practice switching between MPH and KPH See how fast you can run/throw
8 Identify your driver and routeSPTC Identify your driver and route
9 We’ll use a 10 x 10 grid to choose positions -SPTC We’ll use a 10 x 10 grid to choose positions - Once we get out there, make sure you record your position 10 ft
10 Back Inside How fast was the vehicle going?SPTC Back Inside How fast was the vehicle going? Why did you all get different speeds? Is there any pattern to your answers?
11 Let’s figure out the angleSPTC Let’s figure out the angle Side a = ____ Side b = ____ Angle C = ____
12 SPTC Law of Cosines Side c = _____
13 Now we can find A using Law of SinesSPTC Now we can find A using Law of Sines Angle A = ____
14 Repeat the process to find the angle you measured fromSPTC Repeat the process to find the angle you measured from Side a = ____ Side b = ____ Angle C = ____ Side c = _____ Angle A = ____
15 SPTC
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18 Discussion Are your answers more similar than before?SPTC Discussion Are your answers more similar than before? Are they exactly the same? Why might that be? Whose measurements were the most accurate? Whose were the least accurate? What advice would you give someone trying to measure speed using a radar gun?
19 Now what velocity do you think the vehicle was going?SPTC Now what velocity do you think the vehicle was going?