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Unformatted text preview: brown (twb493) – Reflection 2 – turner – (57340) 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 9) 10.0 points Firstly, we might want to know the times at which certain events occur, such as when the cart gets to the end of the track. One way to find this is by editing the condition of the while loop. Currently the condition is set to t < 10 s , but loop conditions are rather flexible. Change the loop condition so that it ends as soon as the cart gets to the end of the track. You can refer to the x, y, and z components of the cart’s position using cart.pos.x , cart.pos.y , and cart.pos.z , respectively. Note that the left and right ends of the track are located at the positions x=-1 and x=1, respectively. With an initial speed of 5 m/s, how many seconds does it take the cart to reach the end of the track? (We will use this same initial speed throughout the assignment.) 1. 0.1s 2. 0.3s 3. 1.5s 4. 0.4s correct 5. 0.7s 6. 0.6s 7. 1.7s 8. 2.0s 9. 0.8s 10. 1.0s Explanation: 002 (part 2 of 9) 10.0 points Let us investigate the effect of a 10 N net force, vector F = ( 10 , , ) . What could this force represent, physically? 1. A kick given to the cart just as it begins to move 2. Friction due to sliding on the track 3. Air resistance on the cart 4. A fan attached to the cart, blowing steadily correct 5. Gravity pulling down (-y direction) on the cart 6. A spring affixed to the left end of the track and the cart 7. The normal force of the track on the cart Explanation: 003 (part 3 of 9) 10.0 points Change your code to use the above force. At what time (in seconds) will cart reach the end of the track? 1. 0.62s 2. 0.24s 3. 0.56s 4. 0.31s correct 5. 0.36s 6. 1.0s 7. 0.07s 8. 0.22s 9. 0.13s 10. 0.81s Explanation: 004 (part 4 of 9) 10.0 points brown (twb493) – Reflection 2 – turner – (57340) 2 Now try a 10 N force in the opposite direction, vector F = (− 10 , , ) . Which of the following is a complete description of the cart’s behavior over time? 1. The cart moves to the left with a constant speed 2. The cart first moves to the left with a decreasing speed, turns around, then moves to the right with an increasing speed 3. The cart moves to the right with a de- creasing speed 4. The cart first moves to the left with an increasing speed, turns around, then moves to the right with a decreasing speed 5. The cart moves to the left with an in-...
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This note was uploaded on 04/13/2011 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
- Spring '08