Physics Review QuestionUnit:
MechanicsYear:
1990 Question#:
4Question:
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/sWhat 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 v _{f}. It looks as though you just multiplied the 8 and the 3. That does not answer the
question.
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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 v _{f}.
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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 <sup>2</sup> thus getting 4m/s. To get the correct answer you must plug the given numbers into the formula: and solve for V _{f}
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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 |

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