Wednesday, January 16, 2013

Projectile Motion


This really cool simulation is courtesy of the PhET project at the University of Colorado. Play around with it until you get comfortable and familiar with the controls.

Answer these questions as comments. Don't answer identically to what someone else has already said--either add to his or her response, indicate that you disagree with the response, or answer a question that hasn't been already answered. Please only comment on 2 questions so everyone has a chance to get some points.


  1. What is the range of a golf ball if it is launched at a 40° angle with a speed of 15 m/s?
  2. What is the total time the golf ball from question (1) is in flight?
  3. Neglecting air resistance, how does the launch speed affect the projectiles overall range?
  4. Neglecting air resistance, how does the launch angle affect the projectiles overall range?
  5. Neglecting air resistance, how does the projectile's mass affect the projectiles overall range?
  6. Of the preset choices, which 3 objects appear to be most affected by air resistance? How do you know this?
  7. Neglecting air resistance, what launch angle produces the maximum range for a projectile?
  8. Taking air resistance into account, what launch angle produces the maximum range for a pumpkin launched at a speed of 10 m/s?

14 comments:

  1. The range of the golfball in question 1 is 24m. It travelled that disctance in 2.1 seconds.

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    Replies
    1. Of the preset choices, which 3 objects appear to be most affected by air resistance? How do you know this? the three objects are human/buick/pumpkin this is because of the drag coefficient is the highest on these object.

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    2. I disagree with Jackie, I believe that the three object appearing to be most affected by air resistance are the human, the piano, and the buick because these three objects have the largest surface area, the largest mass, and the highest drag coefficient. These factors make the air resistance more prominent on these objects. I have also discovered, answering question #5, that the mass of the objects without air resistance has no affect on the projectiles overall range.

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  2. Taking air resistance into account, what launch angle produces the maximum range for a pumpkin launched at a speed of 10 m/s? the angle launch should be 40 I got this by pluging in different number and see what the one had themaxium range was for each one. 40 had 11.3m.

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  3. In question 3, the greater the speed the larger range it has and takes longer to reach the ground(greater time). Less speed it has the smaller range it has and it takes less time to reach the ground(smaller time).
    In question 5, the mass doesn't effect the range of the golf ball.

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  4. Taking air resistance into account, what launch angle produces the maximum range for a pumpkin launched at a speed of 10 m/s?
    The angle launch should be 45 degrees. I got this from guss and check. I pluged in different numbers and found that the answer was 45 degrees.

    Neglecting air resistance, how does the launch angle affect the projectiles overall range?
    The bigger the angle degree, the higher the projectile will go.

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    Replies
    1. For the second question. I agree but wanted to add on. The bigger the degree of the angle the less distance it will travel. The smaller the degree of the angle the projectile will not go as high, but it will go farther.

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    2. I would like to add on to the response for question number 4 that was given by Lauren and Brenna. I believe that the ladies were not specific enough with their responses. As the launch angle increases, the overall range will also increase, but this will only happen to a certain point. After playing with the neat tool that Mr. Bearss provided us with above, I believe that the overall range of the projectile will continuously increase until the angle reaches 45 degrees, which is where it reaches its maximum range. After the measure of the angle increases beyond this point, the overall range of the projectile will begin to decrease until after 90 degrees, where it will begin to increase yet again. If this relationship between the range and launch angle was graphed, it would somewhat mimicking a parabolic shape.

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  5. according to the program, the mass of an object doesn't affect the overall range if initial speed and angle of projection are the same. 5

    the smaller the angle, the larger the overall range should be. 4

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  6. After playing around with this for quite some time, I have come to the conclusion that, to answer question #5, no matter how much you change the mass of an object, if you leave the initial speed and the angle alone, and ignore air resistance, the range of the object never changes. I tested this by taking the lovely Buick and changing the mass from 5kg to 5,000,000 kg. The range stayed constant at 25.9m. At first, I did not think that this was exactly right. In my head, it makes sense that the 5,000,000 Buick definitely wouldn't go as far as the 5kg Buick. After thinking this over, I believe that the mass does not matter to projectile motion because the acceleration of gravity in the situation is always 9.8 m/s^2. Is this correct?

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  7. 8. In response to question 8 the angle should be 38.3-43.9 degrees to achieve maximum range of 10.5 Meters. The 10.5 remained the same while the time in flight increased by .1 when the angle increased from 39.7 degrees to 39.8 degrees.

    7. The angle required for maximum range is 37.95-45.96 degrees.
    The time increased by .1 when the angle increased from 38.8-38.9 degrees.

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  8. I agree with Rachel that the mass of the object does not affect the range i know this to be true because when calculating the range you use the variables: angle of trajectory, time, and velocity. Nowhere in the calculations do you use mass therefore mass would have no affect on it (assuming air resistance is negligible)

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  9. 5)according to the program, the mass of an object doesn't affect the overall range if initial speed and angle of projection are the same.

    4)the smaller the angle, the larger the overall range will be.

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  10. Thanks for the replies to this post.

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