physics

A test rocket is fired straight up from rest. The net acceleration is 20 m/s2 upward and continues for 4.0 seconds, at which time the rocket engines cease firing. What maximum elevation does the rocket reach?

  1. 👍
  2. 👎
  3. 👁
  1. well, do the power thing first
    v = 0 + a t
    v = Vi = 20 * 4 = 80 m/s at power cutoff
    at what height did the power stop?
    h = 0 + 0 t + (1/2)(20)(16)
    = 160 meters
    so
    we have Vi = 80 m/s at Hi = 160 meters
    now coast up
    v = Vi - g t
    at top v = 0 , using g = 9.8
    0 = 80 - 9.8 t
    t = 8.16 seconds coasting to peak
    then
    h = Hi + Vi t - 4.9 t^2
    h = 160 + 80 (8.16 = 4.9(8.16)^2

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    A small weather rocket weighs 14.7 N. The rocket is carried up by a balloon. The rocket is released from the balloon and fired, and its engine exerts an upward force of 10.2 N on the rocket. What is the acceleration of the rocket?

  2. physics

    A rocket, initially at rest on the ground, accelerates straight upward from rest with constant acceleration 29.4 . The acceleration period lasts for time 9.00 until the fuel is exhausted. After that, the rocket is in free fall.

  3. Physics

    A 1.8×104 kg rocket has a rocket motor that generates 2.8×105 N of thrust. What is the rocket's initial upward acceleration? At an altitude of 5000 m the rocket's acceleration has increased to 6.3 m/s2 . What mass of fuel has it

  4. Chemistry

    A model rocket is launched straight upward with an initial speed of 45.0 m/s. It accelerates with a constant upward acceleration of 1.50 m/s2 until its engines stop at an altitude of 160 m. A. what is the max height reached by the

  1. Physics

    A rocket that weighs 7840 N on earth is fired. The force of propulsion is + 10 440N. Determine a) the mass of the rocket, b) the acceleration of the rocket, c) the velocity of the rocket at the end of 8.0 s.

  2. Physics

    A model rocket is launched from rest with an upward acceleration of 6.30 m/s2 and, due to a strong wind, a horizontal acceleration of 1.50 m/s2. How far is the rocket from the launch pad 5.30 s later when the rocket engine runs

  3. math

    a model rocket is projected straight upward from the ground level. It is fired with an initial velocity of 192 ft/s. How high is the rocket after 10 seconds? When is the rocket at a height of 432 feet? What is the maximum height

  4. Physics

    A small 6.90-kg rocket burns fuel that exerts a time-varying upward force on the rocket. This force obeys the equation F=A+Bt2. Measurements show that at t=0, the force is 119.0 N , and at the end of the first 2.40 s , it is 193.0

  1. Physics

    A small 7.10kg rocket burns fuel that exerts a time-varying upward force on the rocket. This force obeys the equation F = A + Bt^2. Measurements show that at t = 0, the force is 121.0N, and at the end of the first 2.10s , it is

  2. Physics

    A model rocket is launched straight upward with an initial speed of 50 m/s. It accelerates with a constant upward acceleration of 2.00 m/s^2 until its engines stop at an altitude of 150 m. a) What is the max. height reached by the

  3. Physics

    A test rocket is launched vertically from ground level (y=0m), at time t=0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 97 m and

  4. physics

    A model rocket is launched straight upward with an initial speed of 60.0 m/s. It accelerates with a constant upward acceleration of 2.00 m/s2 until its engines stop at an altitude of 130 m. (a) What is the maximum height reached

You can view more similar questions or ask a new question.