Baseball Physics Assessment
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Baseball Assessment 1
In baseball, there are rules about what types of bats and balls players can use. These rules help make sure games stay fair and fun! Umpires and league leaders can choose the bats and balls. But other things also change how the game is played that no one can control—like the weather, how high the stadium is built, and how strong the players are. Answer the questions below to see how these things affect a baseball game!
Weather Conditions and Pitch Speed
Look at the graph on the right. It shows how wind speed changes how fast a pitch travels.
The line shows what happens to the ball's final speed when headwind blows against it.
Points A, B, and C show three fast pitches thrown with the exact same starting speed, but into different amounts of wind.
Data source: Kagan, D. The physics of pitching in the wind. Chico State Physics.
Pitch Speed versus Wind Speed final pitch speed (mph) wind speed (mph) 88 87 86 85 84 83 82 0 2 4 6 8 A B C
Question 1) Draw force arrows on the three pictures below (A, B, and C) for each point on the graph.
Show all the contact forces pushing or pulling on each baseball after it leaves the pitcher's hand. Use longer arrows for stronger pushes and shorter arrows for weaker pushes. Make sure to show which way the air is pushing on the ball.
A
Wind: 0 mph
B
Wind: Medium
C
Wind: Strong
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Question 2) Use your drawings from Page 1 to help answer this question:
Kinetic energy (KE) is the energy of moving things. If all three pitches (A, B, and C) had the same amount of kinetic energy right when they left the pitcher's hand, will they all have the same amount of kinetic energy when they reach home plate? Why or why not?
Question 3) How could you test your idea from Question 2 using materials we have in our classroom?
Plan an experiment to test what happens to the pitches. First, list which classroom items you would use to represent the baseball items. Then write down your step-by-step plan.
The items and objects I will use in my experiment:
| Baseball items | Classroom items used to act like baseball items |
|---|
| Bat | |
| Pitcher | |
| Ball | |
| Wind | |
Other tools needed to measure and collect data:
My plan for setting up and carrying out my investigation:
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Showing and Explaining How Bat Weight and Bat Speed Are Connected
The table below shows how fast a major league batter swings bats with different weights (mass). The weight of the bat was changed, and the swing speed was measured for each bat.
| Mass of the bat
(grams) | Bat swing speed
(mph) |
| --- | --- |
| 284 | 74 |
| 340 | 70 |
| 652 | 71 |
| 907 | 62 |
| 964 | 62 |
| 1191 | 61 |
| 1361 | 57 |
Bat Swing Speed vs. Mass of the Bat bat swing speed (mph) mass of the bat (grams) 0 20 40 60 80 100 0 500 1,000 1,500
Question 4) Plot the points from the data table onto the graph above.
Question 5) After plotting your points, draw a straight line through them that shows the overall pattern (a line of best fit).
Question 6) Use your line to guess (predict) how fast a batter could swing a bat that weighs 779 grams.
Record your prediction here: mph
Question 7) A batter pushes each bat with the same strong force from their hands. Why does the bat swing slower when the bat is heavier?
Explain what happens in terms of cause and effect using forces, energy transfer, and motion (kinetic) energy.
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What makes a bigger difference for the kinetic energy of the bat and ball: increasing the speed of the swing or increasing the weight (mass) of the bat?
| Bat weight
| (g) | Speed of ball after contact (mph) |
|---|
| 570 | 68.5 |
| 710 | 73.0 |
| 850 | 76.2 |
| 990 | 78.6 |
| 1,140 | 80.4 |
| Bat swing speed
| (mph) | Speed of ball after contact (mph) |
|---|
| 20.5 | 60.2 |
| 27.3 | 68.8 |
| 34.3 | 76.2 |
| 41.0 | 83.8 |
| 47.9 | 91.4 |
Question 8) Use the data in the tables above to figure out what speeds up the baseball more after it is hit:
Does increasing the weight of the bat or increasing the swing speed of the bat make a bigger difference in the ball's final speed? Show any calculations or math comparisons you used to find out.
Question 9) Air and High Stadiums:
Coors Field in Denver, Colorado is built high in the mountains (5,200 feet above sea level). High up in the mountains, the air is thinner, meaning there are fewer air particles pushing against moving objects. Imagine the tables above were recorded near the beach (at sea level). How would the numbers in both tables change if the test was done at Coors Field where the air is thinner? Would the ball fly faster, slower, or the same? Why?
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Does the type of bat affect the amount of kinetic energy in the bat and ball?
Some people think it is important to have rules about what bats are made of. In Major League Baseball, players may only use wooden bats. College players can use aluminum metal bats. But titanium metal bats are banned (not allowed) in almost all baseball leagues.
A coach says that titanium bats hit balls much harder because titanium is super stiff: "Because titanium bends (deforms) less during a collision, it creates higher push forces on the ball than other bats."
WARNING!
BALLS HIT WITH THIS TITANIUM BAT MAY COME OFF HARDER AND QUICKER WHICH MAY REDUCE REACTION TIME FOR DEFENSIVE PLAYERS. PLEASE WARN EVERYONE WHEN USING THIS TITANIUM BAT. FAILURE TO ALERT COULD RESULT IN INJURY.
Warning shown on the bat label
Question 10) Does the warning on the bat label support both parts of the coach's claim about forces and bending? Why or why not?
Question 11) When objects crash into each other, do you think objects that bend (deform) less spring back quicker or slower than objects that bend more? Why?
Question 12) Imagine you are playing against another team and you know all the facts from this assessment:
• Wind speed and direction | • Stadium height (elevation) | • Bat weight | • Swing speeds | • Bat material
Which single factor would you think about the most when planning how to play against the other team? Why?
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