5 or 10% bonus project in order to improve your grade PDF

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This document contains the project given in the fall 2021 term which was worth up to 10% bonus marks...

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Term Project Situation: During winter, snowstorms in Montreal can change the road conditions in a matter of minutes. The roads become slippery as the coefficient of friction of the road changes with temperature, snow, and ice conditions. It is desirable to analyze the problem to help road users understand the physics of the phenomenon. To achieve your goal, you need to apply the correct kinematic techniques using the physical equations to relate displacement, velocity, acceleration, and time. In addition, you are required to select the ideal kinetic technique for the defined situation.

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Problem Description: Bus drivers often need to drive up or down a hill in Montreal. Some of these buses are rear-wheel driven (motor torque only transfers to rear wheel; front wheel spins freely). Your job is to describe the forces involved in a bus travelling up or down a 20º inclined hill. The two conditions are: 1) Driving up the hill Hint: assume that the bus is a rear-wheel drive, accordingly friction is only applied to the rear wheels. (i.e., front wheels do not have friction). 2) Braking down the hill Hint: brakes are applied to lock all wheels; accordingly, all wheels have friction. For One of the Two Conditions Above: a) Draw the free body diagrams of the bus with its passengers. b) Determine if/how the number of passengers (𝑛𝑝 ) on the bus affects whether the bus can move up or down the hill in a controlled manner at constant velocity under the following road conditions: • Dry road: 𝜇𝑠 = 0.7 𝑎𝑛𝑑 𝜇𝑘 = 0.6 • Wet road: 𝜇𝑠 = 0.55 𝑎𝑛𝑑 𝜇𝑘 = 0.4 • Icy road: 𝜇𝑠 = 0.15 𝑎𝑛𝑑 𝜇𝑘 = 0.1 • Hints: i. You may need to find the proportional loading of each wheel ii. Recall that friction is a reactive force where F =µsN is the maximum threshold for no slip iii. A negative 𝑛𝑝 is not necessarily incorrect. Please think about what it means. c) Describe in your own words what is the meaning of the numbers found, according to the situation described above.

Page 2 of 2 Case Study Analysis: • There is a total of 6 cases to analyze: 3 with driving up and 3 with braking down. • You do not need to do all the 6 cases. • Your case study needs to include the analysis of the bus going up or down under all three illustrated road conditions (dry, wet, and icy). Bus Specification (2D): • Length: 12.19 m and Height: 4.38 m (includes height of wheel) • Mass: 11000 kg (mass uniformly distributed in the bus) • Wheels: 2 m from front and back People on Board: • Driver: 1 person, 80 kg, located at 1 m from the front • Passengers: 𝑛𝑝 persons, 60 kg per person, assume equivalent point mass of all passengers is located at 3 meters from the back of the bus. • Height-wise, the center of mass of all persons is located in the middle of the bus (i.e., h = 4.38/2 = 2.19 m from the ground). Hibbeler Engineeri ng Mechanics: Dynamics, Fourteenth Edition, Pearson, 2016

Project Submission: • This project is a Group submission. • Each group is made up of 2 students who must be from the same tutorial section, exceptions are only through a permission from the course professor. • Please submit your project work in PDF format through the submission tab titled “Project Repport Submission” that will be found under the global title “Bonus Project”. • Due Date: The project needs to be submitted through the course Moodle site no later than Thursday, December 2nd, 2021. Project Grading: If you choose to only analyze 1 condition (driving up or braking down), then the project will be worth up to maximum bonus of 5% of your total grade. You can choose to analyze both conditions for a maximum bonus of up to 10% of your total grade. Quality of analysis and completeness of the report (properly expressed objective and background theory, clear figures, etc) will be of upmost importance and strictly marked. Report Format: Please consult the “Report Writing Guidelines” for suggested sections....