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Need help finding speed and traveling distance for this physics problem?

Update:

A 400-kg car is at rest. A forward variable force F = 2000t Newton (t is time in s) are acted on the car. What is the speed and traveling distance after 5.0 s?

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  • 6 years ago

    A m = 400-kg car is at rest. A forward variable force F(t) = 2000t Newton (t is time in s) are acted on the car. What is the speed and traveling distance after T = 5.0 s?

    We have A(t) = F(t)/m so Aavg = Favg/m = 1/(mT) * INT(2000 t dt)|0 to 5 = (1/5)*1000*25/400 = 12.5 m/s^2.

    In which case:

    V = Aavg T = 12.5*5 = 62.5 m/s

    S = 1/2 Aavg T^2 = (1/2)*12.5*25 = 156 m. ANS.

  • Looks like an impulse problem. Impulse is force*time.

    Force*time = mass*(change in velocity)

    Using this equation,

    2000(5) = 400(change in velocity)

    25m/s = change in velocity

    Since it started at rest, your speed after 5s is 25m/s

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