-Idea: Give lab practicum challenges at the beginning of units, but do them at the end. This unit is landing a ball moving horizontally off of a partially ramped track onto a cup on the floor. For more advanced students, you can launch a ball at an angle and try to hit a cup at either the same starting height or on the floor.
Continue into this unit from the idea of the object dropped from a building at the end of last unit. To review free fall forces and acceleration, you could show this video: Feathers and Coins in a Vacuum. Use the same scenario now, except that the ball is throw horizontally forward. Does the dropped or thrown ball take more time to hit the ground?
-Use the sound made from dropping golf balls to demonstrate if objects hit the ground at the same time or not.
- Drop from same height, same time- what do you hear?
- Drop from different height, same time- what you hear?
- Throw horizontally and drop from same height at the same time- predict like from building one of the three options: dropped ball hits first because it has a shorter distance, throw ball hits first because it's faster, or because of divine intervention they hit at the same time?
- Demonstrate them hitting at the same time further by showing what happens if I throw upwards and downwards
- Does it matter how hard I throw it? What affects when they hit? (height, acceleration, horizontal launch)
- Video demo: Mythbusters bullet fired vs. dropped or Shoot-n-Drop a Ball Slow-mo video
- Post-it note the wall/screen to follow the path of a projectile for set time intervals from a video. This video here should do the trick: 2 Dimensional Projectile in Slow Motion
- What do you notice?
- What does horizontal and vertical spacing tell us about the horizontal and vertical speeds?
- How can we explain this? Is there anything to speed it up or slow it down horizontally or vertically? How many forces are on it? (Is it still being touched?)
- What shape is it?
- Horizontal constant speed equation: horizontal speed = d/t (d=vt)
- Vertical constant acceleration equation: y=1/2at^2 + tVoy (initial vertical velocity), a=-10m/s/s if in Earth's gravitational field
-Unit 6 Worksheet 1 - Vertical Projectiles Only
-If there is a person throwing a ball horizontally from the top of a building, what are some questions I could ask you about the situation?
- How much time is it in the air? How far from the base does it land?
- Draw a motion map of this to scale. Draw arrows for both the horizontal and vertical components.
- Also make a "t chart" of each variable for every second until it hits the ground.
- What is the actually speed of the ball right before it hits the ground? The angle with the ground?
-Unit 6 Worksheet 2 - Projectiles with initial horizontal velocity
-Lab Practicums:
- Land ball rolling off of a track with a ramp onto the top of a cup on the floor
- Launch a ball at an angle from the table to hit a cup at the same height
- Launch a ball at an angle from the table to hit a cup on the floor
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