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Curveball vs. Fastball

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In CurveBall, set the Location to Cleveland, choose a Right Handed pitcher and set the Speed to 85 mph and the Spin, Release , and Angle to 0.0.

Step 1.

These initial conditions show a fast ball. What happens to the fastball with 0.00 release spot and a 0 release angle? The ball goes straight over the plate.

Step 2.

Repeat Step 1 but this time make the ball curve by making it Spin 500 rpm. Will the umpire call this a ball or a strike? Why? The ball curves off to the right of the plate (as viewed from behind the plate). This is a strike; it is over the plate but not down the center.

Step 3.

Increase the Spin to 1200 rmp. Is it a strike or a ball?

This is a ball, the ball passes outside the plate.

Step 4.

Complete the chart below using CurveBall setting the spin to 1200 rpm for the curve ball. Record the distance from the center of theplate as displayed on the screen. Above the plate should be positive distances, and below the plate should be negative distances. Record the distances for the given release spot. Repeat this for a Left Hander and record your results.

Answers will vary. Samples are shown below:

Release Spot (x)

Curveball - Left hander (y)

Fastball - Left hander (y)

Curveball - Right hander (y)

Fastball - Right hander (y)

11 in
0 in
-11 in
0 in
1.00 ft
0 in
-12 in
12 in
2.00 ft
-12 in
-24 in
12 in
24 in
3.00 ft
-24 in
-36 in
24 in
36 in
4.00 ft
-36 in
-48 in
36 in
48 in

Step 5.

Using four different colored pens graph the information on the graph provided. In each of the graphs the Release Spot will be x.

Answers will vary, depending on the answers in Step 4. A sample is shown below:


  1. a) How do the positions of a fastball thrown by a left hander and a right hander compare? The left hander's are all negative and the right handers are all positive. Both form a straight line, but with opposite slopes.

     b) How do the graphs show you this?  The graphs are symmetric about Y = 0.

  2. a) How do the positions of a curveball thrown by a left hander and a right hander compare? They are also straight lines, with the same slope as the fastball, but they are displaced. The right hand curve ball is lower than than the fast ball, the left hand curve ball is higher than the fast ball. To get the ball over the plate (Y=0) you have to release the ball at some distance from the center of the rubber ( X > 0) .

     b) How do the graphs show you this? The graphs cross Y=0 at the same point.

  3. Consider yourself as a hitter.

    a) Are you right handed or left handed? Answers will vary.

     b) Which pitcher would have the more difficult fastball for you to hit? Why? The same side pitcher (right for right .. left for left) will throw a fastball closer to your body than the opposite side.

     c) Which pitcher would have the more difficult curveball for you to hit? Why? For a right handed batter with a left handed pitcher, the curveball curves away from the batter. For a left handed batter with a right handed pitcher, the curveball curves away from the batter.

Related Pages:
Lesson Index
Aerodynamics Index


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Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: Thu, Jun 12 04:47:14 PM EDT 2014

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