Collision in Two Dimensions

The police are investigating an accident. They have determined that the mass of car A is 2275kg and the mass of car B is 1525kg. From the skid marks and date for the friction btw tires and concerte, the police determined that the cars, when they were locked together, had a velocity of 31km/h at angle of 43 degrees north of the eastbound street. If the speed limit was 35km/h on both streets, should one or both cars be ticketed for speeding?

2 Answers

  • ?
    Lv 6
    1 decade ago
    Favorite Answer




    mAu1 = (mA + mB)v cosθ

    2275u1 = (2275 + 1525) x 31 cos43o

    u1 = 37.9km/h


    mBu2 = (mA + mB)v sinθ

    1525u2 = (2275 + 1525) x 31 sin43o

    u2 = 52.7km/h



    mAu1 = (mA + mB)v sinθ

    2275u1 = (2275 + 1525) x 31 sin43o

    u1 = 35.3km/h


    mBu2 = (mA + mB)v cosθ

    1525u2 = (2275 + 1525) x 31 cos43o

    u2 = 56.5km/h


  • 天同
    Lv 7
    1 decade ago

    Let u1 and u2 be the velocities of cars A and B respectively.

    By resoloving the velocity respectively in directions along the line of impact (i.e. 43 degrees north of the eastbound street) and perpendicular to the line of impact, we have, by conservation of momentum:

    2275(u1).cos(43) - 1525(u2)cos(43) = (2275+1525)(31)

    and 2275.(u1).sin(43) = 1525.(u2).sin(43)

    solve for u1 and u2

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