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Hit Modeler Weather Interactive Simulator

Flight Trajectory

With this simulator you can investigate how a baseball flies through the air by changing the values of the factors that affect the aerodynamic forces on the ball. These are the same forces that generate the drag of an aircraft wing. The flight trajectory is determined by the initial velocity and the relative size of the drag and weight of the ball. We provide a page of results which you can use to check your calculations.

The motion is two dimensional and you can study the trajectory of the ball with selected weather conditions. This page contains instructions on the use of the buttons in the program.

Play Ball!

Please note: the simulation below is best viewed on a desktop computer. It may take a few minutes for the simulation to load.

General Instructions

This simulator is designed to be interactive, so you have to work with the program. All input for this version of the program is made with buttons. To operate a button, use your mouse to move the cursor over the button, then left click on the mouse to “push” the button. The current values of variables are presented to you in boxes. A black box with cyan numbers are inputs to the program which are set by the selected buttons. A white box with black numbers is an output box and the value is computed by the program.

Screen Layout

The program screen is divided into two parts:

  1. At the top of the screen is the graphics window. The graphics window shows the trajectory of the hit ball. The simulation is two dimensional and you are looking parallel to the ground. Weight and aerodynamic drag are the only forces acting on the ball. Along the top of the window, the height and distance from the plate are updated during the flight. There is a wall set at 375 feet from home plate. The ball is launched at 100 mph at 45 degrees to the horizon.
  2. At the bottom of the screen are the values of the inputs to the program and the input buttons. The active button is shown in yellow. The default conditions are an Average Day with no wind and a default drag coefficient. The average day is based on an NASA model of the atmosphere and how the pressure and temperature change with altitude. You change the temperature, the atmospheric pressure, and the relative humidity of the air by using the appropriate button. The program then calculates the air density that affects the drag on the ball. You can set the wind at your back (+ Wind) or wind in your face (- Wind) and can change the drag coefficient to zero by using the buttons at the right. When you have your conditions set, click on the yellow SWING button at the top to launch the ball into the air. You can save your flight trajectory to compare with a new set of conditions by pushing the blue Save button. And you can clear all of the graphics by pushing the orange Clear button.

Have fun!

Learn more about the aerodynamics of baseball.

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