FORCE AND MOTION May the Force Be With You
For Me: Understanding Car Crashes: It's Basic Phyics-the entire unit plan
Also: Nascar: Acceleration Booklet-lessons
Also: State your Claim-Eduation.com
Prove it with Evidence-Education.com
Essential Question: What is the relationship between Force and Motion?
Learning Targets: I Can Statements
*I can demonstrate how forces can oppose the motion of an object
*I can describe a force by its magnitude and direction
*I can construct a force diagram
*I can describe how net force affects an object's direction and/or speed.
*I can demonstrate how forces are related to Newton's 1st Law of Motion (inertia).
*I can apply knowledge about forces to solve a problem by designing a solution.
Day ! GRAVITY WEBQUEST
Complete the web quest on Gravity
Activity: Watch the first few minutes of Toy Story 2
Balanced vs. Unbalanced Forces
Activity: Read, Balanced vs. Unbalanced Forces
At the end of the web version there is a section called, Check Your Understanding. Write your answers in the worksheet your teacher has provided you.
Activity: Complete the Balanced vs. Unbalanced Forces Worksheet from the Physics Classroom-Your teacher will give this to you.
Write down any type of movement/stop that you see in these first 4 minutes of the movie
Day 2: Gravity Pitch Gizmo
Day 3: Group Activity: Complete the Pre-Assessment called, "Is The Force With You?"
When you complete this I will ask you to share your answers with the people at your table. Then we will share out with the class. If you need to write in the correct answer NOW is the time to do this.
Activity #1 Watch the PPT Force and Motion and take notes in you ISN. The PPT will tell you how to take the notes. You may want a couple of colored pencils to enhance your drawings.
INFORMATION:
Forces have a magnitude (strength) and a direction. Forces can be represented as arrows with the length of the arrow representing the magnitude of the force and the head of the arrow pointing in the direction of the force. Using such arrows, the resulting force (net force) and direction can be determined.
Forces acting on an object can be balanced or unbalanced.
Balanced forces will cause no change in the speed of an object.
Balanced forces acting on an object in opposite directions and equal in strength, as shown in the arrows above, do not cause a change in the speed of a moving object.
- Objects that are not moving will not start moving if acted on by balanced forces.
- Or, in a tug of war, if there is no movement in the rope, the two teams are exerting equal, but opposite forces that are balanced. Again, the resulting force (net force) is zero.
Unbalanced forces are not equal, and they always cause the motion of an object to change the speed and/or direction that it is moving.
- When two unbalanced forces are exerted in opposite directions, their combined force is equal to the difference between the two forces.
- The magnitude and direction of the net force affects the resulting motion
- This combined force is exerted in the direction of the larger force
- For example, if two students push on opposite sides of a box sitting on the floor, the student on the left pushes with less force (small arrow) on the box than the student on the right side of the box (long arrow).
- The resulting action (net force: smaller arrow to the right of the = shows that the box will change its motion in the direction of the greater force as shown below:
- Or, if in a tug of war, one team pulls harder than the other, the resulting action (net force) will be that the rope will change its motion in the direction of the force with the greater strength/magnitude as shown below:
- If unbalanced forces are exerted in the same direction, the resulting force (net force) will be the sum of the forces in the direction the forces are applied.
- For example, if two people pull on an object at the same time in the same direction, the applied force on the object will be the result of their combined forces (net force or longer arrow to the right of the =) as shown below
- When forces act in the same direction, their forces are added. When forces act in opposite directions, their forces are subtracted from each other.
- Unbalanced forces also cause a nonmoving object to change its motion
- If there is no net force acting on the object, the motion does not change. If there is a net force acting on an object, the speed of the object will change in the direction of the net force.
NEWTON'S FIRST LAW:
Newton's first law of motion is often stated as An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
READING ACTIVITY: Read this chapter on Newton's First Law
Note Taking Activity: Make a flip book and take notes on the chapter, Newton's First Law
STEM Car Crash Project
Essential Question: How can you design a car that can keep an egg (passenger) safe under normal driving conditions and in the event of a crash?
Key question(s) • How do people survive major collisions? • How does physics explain the effectiveness of seat belts and airbags?
Objectives Students will: • describe a collision in terms of momentum changes and impulse • design, build, test, and evaluate a safety device to protect an egg during a collision
Crash Course Definitions:
impulse: product of force and time interval during which the force acts impulse equals change in momentum
F∆t=∆(mv)
impact: qualitative term for force
Background information
When Newton described the relationship between force and inertia, he spoke in terms of two other physics concepts: momentum and impulse. Newton defined momentum as the product of an object’s mass and velocity. Newton defined impulse as the quantity needed to change an object’s momentum.
To change an object’s momentum either the mass or the velocity or both change. If the mass remains constant, then the velocity changes and acceleration occurs.
In his second law, Newton said in order to accelerate (or decelerate) a mass, a force must be applied. The way it’s often expressed is with the equation F=ma. The force “F” is what’s needed to move mass “m” with an acceleration “a.” The greater the force on an object, the greater its acceleration, or the greater its change in velocity, and therefore, the greater its change in momentum. How long the force acts is also important. Apply the brakes briefly to a coasting car and you produce a change in its momentum. Apply the same braking force over an extended period of time and you produce a greater change in the car’s momentum. So to change something’s momentum both force and time are important. The product of force and the time it is applied is called impulse.
impulse = force x time interval
Day 1: Watch the video, "Understanding Car Crashes: it’s basic Physics" and "Understanding Car Crashes: Where Physics Meets Biology". These videos are your research and that the information you learn from them should help to inspire your car design. While watching the video get out your ISN and take notes.
Day 2: Look at the materials list below and the constraints you are required to abide by. Plan out your design by providing a detailed diagram that includes amounts and sizes of everything. When you have a teacher sign off you may begin construction of your car.
The Materials Parameters and Constraints:
1. Your group will submit a proposal to this problem; test your solution using the following experiment specifications;
The car must “seat” one egg.
Size Length= 20 cm minimum, 30 cm maximum
Width= 5 cm minimum, 7 cm maximum
Height= 5 cm minimum, 15 cm maximum
Four wheels, any source is acceptable, even hand made
Two axles
Legal Features
• Bumpers
• Roll bars
• Air bags
• Crush zones
• Break-away parts
• Seat belts
• Form-fitting seats
Illegal Features
• Brakes-of any kind
• Parachutes, scoops, or any other device that slows the vehicle’s speed
• Extra wheels
• Foreign objects applied directly to (or wrapped around) the egg “passenger” for protection (cotton, Styrofoam, bubble wrap, etc.)
• Tape, staples applied to passenger
Materials List
* straws
* beads
* craft sticks
* rubber bands
* glue -glue gun
* tape
* 1 dowel
* 1 snack size baggie
* 4 cottonballs
* styrofoam-see above restrictions
* any other materials must be approved prior to use
Proposal for Solution: Your group must first write a proposal for solution to submit to your teacher. Start your proposal for solution with “I (We) propose to…” This would be followed by a brief description of your solution. This solution would include the following:
1. Design sketch/description
2. Materials list
3. Group members Roles/Responsibilities
**Once your proposal is completed and approved you may construct and test your vehicle.
Day 3: Construction Day
Day 4: Testing Cars for Crashworthiness Day
TESTING PARAMETERS:
Data collected during testing must include
1. the average speed of the car with the egg
2. the “injuries” suffered by the “passenger.”
Remember that The final portion of this challenge is to evaluate your car, and propose a redesign modification to improve your initial solution. Good Luck!!!
Day 5: Competition Day-Here it is!! Will your egg have :
1. NO Injury
2. An Injury -cracked egg
3. A Fatality-yolk exposed
Day 5: Competition Day-Here it is!! Will your egg have :
1. NO Injury
2. An Injury -cracked egg
3. A Fatality-yolk exposed