Distance and Angle

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Updated on Mar 26, 2014

Grade Level: 5th - 8th; Type: Physics

Objective:

To find out the angle that allows a thrown ball to travel the furthest.

The purpose of this experiment is to attempt to throw a ball the greatest horizontal distance possible by using different angles.

• What angles help a ball travel further?
• How does the force of gravity affect the distance a ball can travel?
• What is the force of gravity?
• What technologies make use of the relationship between angle above the horizon and distance?

It seems that the best way to through a ball is to throw it straight out as hard as possible. After all, throwing it straight in the direction you want it to travel will give the ball the maximum amount of momentum in that direction. Gravity, however, affects the trajectory of a thrown object. Compensating for the force of gravity is one way to help a thrown object, such as a ball travel further. This can be achieved by throwing the ball at an angle above the horizon in the direction you want it to travel. But this angle must be carefully selected as ball that is thrown too high off the ground will not travel its maximum distance. Knowing how high to throw a ball to maximize its horizontal distance is important in order to learn about how maximize how far it can travel.

• A small ball, such as a baseball or a softball
• A protractor
• A straw
• Tape
• Scissors
• A string
• A small weight, such as a washer or fishing weight
• A few friends
• A tape measure
1. You will use a modified protractor to measure the angle of the ball as it is thrown. Start by taping the straw to the flat part of the protractor.
2. If the protractor has a hole through the center of the flat edge, thread the string through this. If not, tie the string to the center of the straw.
3. Cut the string to a length of about 6 inches.
4. Tie the weight to the other end of the string.
5. Make sure that if you hold the protractor so that the flat edge is up and parallel to the ground, the weight pulls the string to 90 degrees.
6. Have a friend hold the protractor so that when they look through the straw and lift it off the horizon the string moves towards the numbers higher than the 90 degree mark.
7. Go out to a large open space.
8. Begin by throwing the ball as far as you can as close to horizontal as you can.
9. Have the friend with the protractor watch the ball through the straw, catching the string with his or her finger when the ball is at its highest off the ground.
10. Subtract 90 from the degree marked with the string on the protractor.
11. Record this information on a chart such as the one below.
12. Have another friend measure the distance that the ball travelled, using a tape measure.
13. Record this information on the chart.
14. Repeat steps 8-13 two more times. Try to throw the ball at the same strength as you did in the earlier trials.
15. Throw the ball so that it rises about 10 degrees above parallel from the ground.
16. Repeat steps 9-13 as before.
17. Perform three trials at 10 degrees, and then continue the experiment with three trials each at 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees and 90 degrees.
18. Repeat steps 9-13 after each throw.
 Trial Angle on Protractor True Angle (subtract 90 degrees) Distance 1 (horizontal) 95 degrees 5 degrees 25 meters 2 (horizontal) 93 degrees 3 degrees 3 (horizontal) 88 degrees -2 degrees 4 (10 degrees) 111 degrees 11 degrees 5 (10 degrees) 6 (10 degrees)

Terms/Concepts: Angle; Distance; Horizontal; Vertical; Force; Gravity; Compensate

References:

Writer and educator Crystal Beran is rarely seen without a pen. Her adventures have brought her to four continents and her quest for answers has led her to discover more questions than she could fill all the pages with. She currently resides in Northern California, where she can be found sipping tea and writing books.