Trajectory in Gravity
Acceleration: This simulation allows you to launch an ion propelled imaginary spaceship from the surface (Y > 0) of a moon or small planet with no atmosphere and a gravitational field (0.124 meters per second per second). Type in the ship orientation ( force direction) and thrust duration (time, s = .5*a *t^2), and then click ENTER ... button. This enters desired ship orientation and duration of engine burn into the spaceship ion propulsion engine control computer. The computer uses the accelerometer sensor inputs to regulate thrust so as to maintain desired acceleration. Engine burn does not begin and Time does not change until an Engine Control Button is clicked. The STOP ENGINE button advances time by an amount specified (Thrust Duration as entered) at zero thrust and zero fuel consumption. During the stop engine period the spaceship will be in freefall, and it will continue to move under the influence of gravity (-.124 M/S/S ).
Start by launching the spaceship straight up (90 degrees) at full thrust for a period of 100 seconds and then change period to 1800. Click STOP ENGINE and note that spaceship continues to travel in a freefall trajectory until ship impacts ground. Note that the entire trajectory of spacecraft is recorded in scrolling textbox at bottom of page. Make a graph of Elevation verses time on a sheet of graph paper. From the data recorded determine gravitational acceleration.
Note: Ship Orientation and Course are independent of each other.
Exercise: Launch Missile at 45 degrees for 100 seconds. Then press STOP ENGINE to advance time in freefall until ground is impacted. Make a plot of Trajectory (Elevation verses X) on a sheet of graph paper.
Back to Chapter 2