quick help on a question?

Q: A car that has a speed of 15mph accelerates for 7seconds at a rate of 2mph/s. What is the velocity of th object at the end of the acceleration?

AND

Sarah is driving down the highway at 50mph when a deer jumps in front of her car. Sarah accelerates for 2 seconds at -20mph/s before striking the deer. What is her speed when she hits the deer?

thank you so much for you help.

2 Answers

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  • 1 decade ago
    Favorite Answer

    a= 2mph/sec (strange unit but it's all we need here so no problem)

    v = v0 + a*t

    v = 15mph + (2 mph/s)*7s = 29mph

    for the second part, it's just the same equation with different inputs..

    v = v0 + a*t

    v = 50mph + (-20 mph/s)*2sec

    v = 10mph

    EDIT: by the way, make sure to *always* quote results with their units. some teachers mark down for failing to carry the units through and quoting the final result *with* their units.

    i do.

  • Anonymous
    1 decade ago

    15 + 2(7) = 29

    50 - 2(20) = 10

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