- Projectile motion
*without*air resistence; - Projectile motion
*with*air resistence.

1) Play with the mass slider and look at the particle path and max distance. What happens to the motion of the ball when you change the mass?

2) Play with the angle slider and look at the max distance. For any given velocity or mass, what angle always gives the maximum distance?

3) Next, test the accuracy of the applet. For your choice of initial velocity, angle and mass verify the horizontal distance (range) the applet gives with a hand calculation (Show your work). Do the values agree?

4) Plot exercise A: Set the angle of your projectile to any value between 15 and 75 degrees. Pick any mass that you like and make sure that air resistance is turned off. Record the distance, height and time for several different values of velocity. Record about 10 runs and try to space out the velocity values that you use. Make the following plots:

i. |
distance vs. velocity |

ii. |
height vs. velocity |

iii. |
time vs. velocity |

From your plots and your knowledge of the equations governing projectile motion, what type of function best describes each of your plots?

5) Plot exercise B: Set the velocity of your projectile to any value between 20 and 80 m/s. Pick any mass that you like and make sure that there is no air resistance. Record the distance, height and time for many different values of the angle. Record about 10 runs and try to space out the angle values that you use. Make the following plots:

i. |
distance vs. angle |

ii. |
height vs. angle |

iii. |
time vs. angle |

From your plots and your knowledge of the equations governing projectile motion, what type of function best describes each of your plots?

1) Now turn the air resistance on by clicking the checkbox. Now what happens as you change the mass? Can you identify a trend? Make a plot of the horizontal distance (range) as a function of mass. To do this, pick fixed values for the velocity and angle (between 10 and 80 degrees, for clarity).

2) With air resistance still on and use the applet to estimate the angle that gives the maximum distance for an initial velocity of your choice. Is it still 45 degrees? Repeat this for several different values of the ball mass and plot your results (i.e. angle for maximum distance vs. mass)

3) Lastly, the air resistance in this model is

- drive faster or slower (change speed);
- turn the car (change direction);
- open or clench your fist (change shape)?

Test your hypothesis with the virtual

4) Draw a free-body diagram of the moving projectile putting your fresh knowledge of Newton's laws to use. Draw in the total force vectors. Don't worry about components yet.

5) Plot exercise C: Set the angle of your projectile to any value between 60 and 75 degrees. Pick a low value for the mass and make sure that the air resistance is turned on. Record the distance, height and time for many different values of velocity. Record about 10 runs and try to space out the velocity values that you use. Make a plot of distance vs. velocity. Make the following plots:

i. |
distance vs. velocity |

ii. |
height vs. velocity |

iii. |
time vs. velocity |

How do these plots compare (in terms of shape) to those from Plot exercise A? What is similar? What is different?

P.S. -- ASK QUESTIONS! That is what this is all about...

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