Physics Review Question Unit: Mechanics Year: 1990 Question#: 4 Question: A car moving at a speed of 8.0 meters per second enters a highway and accelerates at 3.0 meters per second 2. How fast will the car be moving after it has accelerated for 56 meters? (1 ) 24m/s (2 ) 20m/s (3 ) 18m/s (4 ) 4.0m/s What is this question really asking? Explanation by: Liz M. [ Return to question menu ] Answer 1 24 m/s INCORRECT To answe this question you need to plug the given numbers into the formula and solve for vf. It looks as though you just multiplied the 8 and the 3. That does not answer the question. return to top Answer 2 20 m/s CORRECT You plugged the numbers into the formula:   after doing the calculations, you came up with the answer 20m/s as the final velocity. Good answer. return to top Answer 3 18 m/s INCORRECT I am unsure how you got this answer. Perhaps you divided the 56 by the 3 and came up with approximately 18. To answer this question, you need to plug the given nmbers into formula: and solve for vf. return to top Answer 4 Incorrect INCORRECT I am unsure of how you got this answer. Perhaps you divided the displacement (56m) by the 8m/s getting 7 sec, and then subtracted the 3m/s 2 thus getting 4m/s. To get the correct answer you must plug the given numbers into the formula: and solve for V f return to top What's this question really asking? The question is asking if the student understands how to plug in the right numbers into the right formula. It is a case of thinking it through and figuring out which variable you need to solve for. 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.