Your school science club has devised a special event for homecoming. You’ve attached a rocket to the rear of a small car that has been decor

Question

Your school science club has devised a special event for homecoming. You’ve attached a rocket to the rear of a small car that has been decorated in the blue-and-gold school colors. The rocket provides a constant acceleration for 9.0s. As the rocket shuts off, a parachute opens and slows the car at a rate of 5.0m/s2. The car passes the judges’ box in the center of the grandstand, 990m from the starting line, exactly 12s after you fire the rocket. Part A What is the car’s speed as it passes the judges

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Minh Khuê 2 days 2021-07-22T01:05:07+00:00 1 Answers 0 views 0

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    2021-07-22T01:06:38+00:00

    Answer:

    Explanation:

    Acceleration acts for 9 s and deceleration acts for 12 – 9 = 3 s.

    Total distance covered = 990 m

    initial velocity u = o

    Distance covered while accelerating

    s₁ = 1/2 a 9² where a is the acceleration

    = 40.5 a

    final velocity after 9 s

    v = at = 9a

    while decelerating

    v² = u² – 5 x s₂

    0 = (9a)² – 5 s₂

    s₂ = 16.2 a²

    Distance covered while decelerating = 16.2 a²

    s₁ + s₂ = 990

    40.5 a + 16.2 a² = 990

    16.2 a² + 40.5 a – 990 = 0

    a = 6.5

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