Student Exploration: Shoot the Monkey
Vocabulary: acceleration, free fall, trajectory, vector, velocity
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Eccentric billionaire Veda Hussert has invented a “banana cannon” to help feed the monkeys on her personal wildlife preserve. To feed a monkey high in the trees, simply aim the cannon at the monkey and fire a banana! Unfortunately, the noise of the cannon frightens the monkeys, and they drop out of the tree when they hear the sound.
To hit a falling monkey with a banana, where should Veda aim? (Circle your choice.)
A. Above the monkey B. Below the monkey C. Directly at the monkey
Explain your choice:
The Shoot the Monkey Gizmo™ shows a banana cannon and a monkey. When the cannon fires, the startled monkey drops from the branch.
Click Play () to fire the cannon.
You can use the sliders to change the banana velocity (vInitial) and cannon angle (θ). (You can also drag the cannon barrel.) Make adjustments until the monkey catches the banana.
What were the velocity and angle that you used?
Now try increasing and decreasing the velocity. Assuming the banana is moving fast enough to reach the tree, does the monkey still catch the banana? Describe your findings.
Get the Gizmo ready:
Click Reset ().
Set the initial velocity (vInitial) to 26.0 m/s.
Question: Where should you aim to hit the monkey with a banana?
Experiment: Turn on Show target line. Experiment with the Gizmo, trying several different cannon locations and launch angles. Try aiming above, below, and directly at the monkey.
What always happens when you aim above the monkey’s head?
What always happens when you aim below the monkey’s feet?
What always happens when you aim at the monkey’s body?
Predict: How do you think changing the banana velocity will affect your results?
Test: Click Reset. Turn on Show grid, and drag the cannon to the point (25, 0.0) on the grid. Aim the cannon at the monkey, and try vInitial values of 15.0, 20.0, 25.0, and 30.0 m/s.
How did the banana velocity affect the results of the experiment?