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Homework Help: Basic Physics Questions Need to Check My Answers

  1. Jan 19, 2010 #1
    8. If the displacement of a car was 150 km [E] and the velocity was 50.0 km/h [E], what was
    the time of travel?
    A. 100 h [E]
    B. 3.0 h
    C. 100 h
    D. 3.0 h [E]

    (I divided 150 by 50)

    9. The airport is 60.0 km away and you have 1.00 h to get there. If your speed for the first
    40.0 minutes is 48.0 km/h, how fast must you travel in the remaining 20 minutes to get
    there within the time?
    A. 48.0 km/h
    B. 84.0 km/h
    C. 90.0 km/h
    D. 180 km/h
    ( for this I converted the times to hours then I found the distance it travelled first then I subtracted it from the whole distance it has to travel then I divided the amount it still had to travel by the remaining time)

    10. If the velocity of a car is 16 m/s and it travels for a time of 6.0 s, what is the
    displacement? Express the displacement correctly.
    A. 96 m
    B. 10 m
    C. 96 m
    D. 10 m/s
    (for this I multiplied the velocity by the time it travelled and inferred that it doesnt include direction)

    11. A racoon travels from point A to point B in 11 s. If the racoon was displaced 55 m ,
    what was its velocity? Express the number correctly.
    A. 5.0 m/s
    B. 5.0 m/s
    C. 44 m/s
    D. 66 m/s
    (for this I divided the displacement by the time)

    12. A car driver speeds up from 5.00 m/s [E] to 15.0 m/s [E] in 4.00 s. Determine the car’s
    acceleration.
    A. 40.0 m/s2 [E]
    B. 40.0 m/s [E]
    C. 2.50 m/s2 [E]
    D. 2.50 m/s [E]
    (for this I subtracted the final velocity from the initial velocity and the divided this value from the time)

    13. An 1800 kg Volkswagen travelling at 60.0 km/h impacts into a concrete barrier and stops
    in 0.420 s. The magnitude of the collision force on the automobile is
    A. 2.57 x 105 N
    B. 7.14 x 104 N
    C. 1.26 x 104 N
    D. 1.08 x 105 N
    (for this I first converted the speed to m/s then divided this by the time to get acceleration then I multiplied this by 1800 Kg is this the correct way to do it do i calculate the acceleration by dividing the given velocityby the time or is there another way to do it)
     
  2. jcsd
  3. Jan 19, 2010 #2

    cronxeh

    User Avatar
    Gold Member

    All of the answers are correct

    #13 :

    impulse = mass*speed
    speed = 16.67 m/s
    mass= 1800 kg

    force of collision = impulse/time
     
    Last edited: Jan 19, 2010
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