Physics Review Question Unit: work and energy Year: 1996 Question#: 3 Question: The graph represents the relationship between speed and time for a car moving in a straight line. The magnitude of the car's acceleration is (1 ) 1.0 m/s2 (2 ) 0.10 m/s2 (3 ) 10. m/s2 (4 ) 0.0 m/s2 What is this question really asking? Explanation by: Becky G [ Return to question menu ] Answer 1 1.0 m/s2 INCORRECT Speed is measured in tens on the graph. 1.0 m/s would mean you probably used one tenth of a second instead of 1 sec. Remember, acceleration can be thought of as the slope of a speed vs. time graph, or change in speed divided by change in time. return to top Answer 2 0.10 m/s2 INCORRECT The number 0.10 m/s2 would be much too small. Remember, acceleration can be thought of as the slope of a speed vs. time graph, or change in speed divided by change in time. return to top Answer 3 10. m/s2 CORRECT 10. m/s2 is correct becausetaking the slope of the line gives you this value regardless of what two points you choose to use for change in speed (y) divided by the change in time (x) . Remember, acceleration can be thought of as the slope of a speed vs. time graph, or change in speed divided by change in time. return to top Answer 4 0.0 m/s2 INCORRECT 0.0 m/s2 is wrong because 0.0 m/s2 would indicate the speed is not changing, but clearly the graph shows a changing speed, so it must have some acceleration. Remember, acceleration can be thought of as the slope of a speed vs. time graph, or change in speed divided by change in time. return to top What's this question really asking? Can you read a graph? Do you realize that the slope of a speed vs time graph is acceleration? Can you calculate slope from the graph? -or- use the acceleration formula? return to top This web site is designed and maintained by Science Joy Wagon and may not be reproduced or redistributed without written permission from Science Joy Wagon. Contact with comments.