Flash Animation by Mark Cowan ePhysics, UCLA

Large Simulation

Description: The animation displays a ship traveling over the ocean. The animation also displays a bottle drifting with the ocean current (the bottle is only shown when the speed of the ocean current is not equal to zero. The animation can also be used to show the ship's path, ship's position vector, the polar coordinates of the ship, and the velocity vectors of both the ship and bottle (the animation does not yet show the addition of these velocity vectors). The animation can be used to learn about position vectors, Polar versus Cartesian coordinates, velocity vectors, vector addition using position vectors, and vector addition using velocity vectors.

Instructions:

1. Controlling the velocity of the ocean current-

   1. The speed of the ocean current can be controlled by dragging the red triangle on the speedometer in the lower right hand side of the animation. The bottle, drifting along with the ocean current, will be visible only when the speed of the current is not equal to zero.

   2. The direction of the velocity of the ocean current can be controlled by dragging the red needle of the compass on the right hand side of the animation.

   3. You must first press stop in order to change the ocean current's speed and direction. Press play in order to resume the animation.

   4. Press rewind in order to reset the animation to its initial conditions.

2. Controlling the velocity of the ship-

   1. The speed of the ship can be controlled by dragging the purple triangle on the speedometer in the lower right hand side of the animation. To be more specific, the speedometer sets the speed of the ship relative to the water.

   2. The direction of the velocity of the ship can be controlled by dragging the purple needle of the compass on the right hand side of the animation. To be more specific, the purple needle on the compass sets the direction of the velocity of the ship relative to the water.

   3. You must first press stop in order to change the ship's speed and direction. Press play in order to resume the animation.

   4. Press rewind in order to reset the animation to its initial conditions.

3. Displaying properties of the motion of the ship and ocean current-

   1. Click on the appropriate check boxes in order to display the ship's position vector, the ship's path, the ship's Polar Coordinates, and the velocities of the ship and ocean current.

   2. The ship's Cartesian Coordinates is indicated by the purple segments appearing on the x and y axis'.

   3. The white segments on the x and y axis' provide the Cartesian Coordinates of the cursor. This allows to find the Cartesian Coordinates of any point on the animation. For example, placing your mouse over the center of the coral reef shows that the Cartesian Coordinates of the center of the coral reef are (6,21).

   4. Displaying on Polar Coordinates will also cause the position vector of the ship to be displayed. Converesly, turning off the position vector of the ship will also cause the Polar Coordinates of the ship to be turned off. The Polar Coordinates will not be displayed if the ship is too close to the origin and the angular coordinate will not be displayed if the position vector is to close to the x axis.

   5. Three velocity vector will be displayed when the "velocity vector box is checked", namely the velocity of the bottle, the velocity of the ship relative to the water, and the velocity of the ship relative to land.

      1. The bottle's velocity is identical to the velocity of the ocean current and determined by the compass and speedometer settings of the ocean current.

      2. The ship's velocity relative to the water is displayed as a lavender, dashed vector and is one of two velocity vectors that is located coincidently with the ship. The ship's velocity relative to the water is determined by the compass and speedometer settings of the ocean current.

      3. The ship's velocity relative to the land is displayed as a green, dashed vector and is the second of two velocity vectors that is located coincidently with the ship. The ship's velocity relative to the land is determined by adding the velocity of the ocean current to the ship's velocity relative to the water.