Projectile Problem: Testing Experiment

Aim

Revise your predictions about how far a projectile will fly based on your knowledge of kinematics.

Prior Knowledge

• Motion with constant speed
• Motion with constant acceleration
• Projectile motion

Description of the Experiment

A ball is launched at an angle of 30 degrees and then at an angle of 60 degrees. Make a prediction about how far the ball will fly in each case if the initial launch velocity is 4.8m/s in each case. (With an uncertainty of 0.1m/s.)

• Explain what models/explanations you are using to make your prediction.
• Make a list of assumptions you are making to make your prediction.
• How will each assumption affect your prediction?
• Make a prediction for how far the ball will travel at 30 degrees.
• Make a prediction for how far the ball will travel at 60 degrees.

Now watch the video, take data (there are two trials for each angle) and see if the results of the experiment match your prediction.

Addtional Information

The numbers are often blurry because of the panning camera. Just remember that each number represents 20cm and it is possible to infer the number based on the picture in the previous frame and a little bit of interpolation.

Youtube movies can be stepped frame by frame using the , and . keys on your keyboard. If you want to download the movie to your computer, right-click or control-click HERE.

Questions

• Did either of you predictions agree with the outcome of the experiment? (You should take experimental uncertainties into account of course.)
• If not, can you revise your explanation and/or assumptions to explain why things did not happen the way you expected.