1. A stoplight 20 m to the west turns yellow. Your car is traveling west at 12 m/s. You hit the brakes and decelerate at a rate of 6.0 m/s 2 . Your car stops before it reaches the stoplight (which is considered to be at the origin). A student in a physics class made a picture of this. t o = 0 s x o = + 20 m v o = – 12 m/s a = – 6.0 m/s 2 Which of the following is labeled wrong? 1 x o 2 v o 3 a 4 a & v o 5 all of the values are correct Did the student mislabel anything? x
2. A student in a physics class made a picture of the situation but did not include the signs of the variables. t o = 0 s x o = __ 20 m v o = __ 12 m/s a = __ 6.0 m/s 2 What are the signs of the three missing variables? x o v o a 1 + – – 2 + – + 3 + + – 4 + + + 5 – – + A stoplight 20 m to the west turns yellow. Your car is traveling west at 12 m/s. You hit the brakes and decelerate at a rate of 6.0 m/s 2 . Your car stops before it reaches the stoplight (which is considered to be at the origin). x
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5. 1 + – 2 + + 3 – + 4 – – A bicycle is moving on the road. Its motion is described by the graph below. v o a Below is a mathematical description of the same motion. What should the signs of v o and a be to be consistent with the above graphical description? v t
6. A hot air balloon is stationary in the sky as seen in the picture. A person throws a ball up in the air at 5 m/s. Which set of mathematical representations best matches this process? 1. V f = (5.0 m/s) + (10 m/s 2 ) t 2. V f = ( - 5.0 m/s) + (10 m/s 2 ) t 3. V f = (5.0 m/s) + ( - 10 m/s 2 ) t 4. V f = ( - 5.0 m/s) + ( - 10 m/s 2 ) t 5. Either 2 or 3 are correct Construct a mathematical representation that best matches this process.
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10. A car is moving along the road as seen in the motion diagram below. Which mathematical representation below could match this process? 1. V f = (5.0 m/s) + (10 m/s 2 ) t 2. V f = ( - 5.0 m/s) + (10 m/s 2 ) t 3. V f = (5.0 m/s) + ( - 10 m/s 2 ) t 4. V f = ( - 5.0 m/s) + ( - 10 m/s 2 ) t 5. Either 2 or 3 are correct Construct a mathematical representation that could match this process. x + v final v initial
