|Title:||Circle of Knowledge|
|Subject:||Physics – Momentum Conservation and collisions|
|Description:||Impulse & Momentum. Conservation of momentum , Elastic and Inelastic collisions|
Instructional Unit Content
Standard(s)/Element(s)Content Area Standard AP Physics- Momentum Conservation and Collisions TAG Standard
Advanced Communication skills-8, Creative thinking & Creative problem solving skills, Higher Order Critical thinking skills
The focus of this lesson is to give students an opportunity to apply concepts of conservation of momentum and collisions to safety features in automobiles and traffic systems and see how the physics principles can be applied to real life situations. They would then use the knowledge gained to problem solve a real life situation in the Accident reconstruction Challenge.
At the end of this lesson the student will understand that
a. Total momentum of an isolated system where no external force acts is conserved and that exchange of momentum can take place within the system.
b. Impulse is the change in momentum of an object.
c. The elastic/inelastic nature of collisions is related to the amount of kinetic energy lost by the system during a collision
d. How these principles are applied in automobile safety features and in traffic systems.
How can the principles of momentum conservation and collision be applied to
the design of safety features in automobile systems and traffic systems?
Concept(s) to Maintain
An uncancelled force is only required to change the state of motion of an object.
Evidence of Learning
What students should know:a. Conservation of Momentum is an universal principle b. The impulse exerted is equal to the product of force and time and is equal to the change in momentum brought about by the force.
c. Collisions in which the total kinetic energy is conserved are called elastic collisions and those in which kinetic energy is not conserved are called inelastic collisions.
What students should be able to do:
a. Apply conservation of momentum to decide on probable outcomes of a collision in one and two dimensions
b. Apply impulse- change in momentum theorem to situations
c. Determine the elastic nature of collisions and calculate the loss in energy
d. Apply concepts learnt to explain how safety features in automobiles and traffic systems operate
e. Understand and apply the scientific process to accident reconstruction situations that reflects a good understanding of concepts and the ability to examine a situation from different perspectives and come to a judgment.
1. Pose the essential (focus) question: How has automobile safety improved over the years and how do the physics principles apply to the safety features? Activate prior knowledge by having students name any three principles/laws/phenomenon that they have learnt that can directly apply to the working of these safety features.
2. Students will use prior knowledge to complete the worksheet on identifying the elastic nature of collisions and apply momentum conservation principle to situations similar to real life car crashes. On completing the worksheet, as a class students will discuss to decide which outcomes are probable and based on the outcome , the elastic nature of the collision.
3. Students will participate in a class discussion of relating these principles to the working of safety features (both passive and active) in automobiles and highway systems. The discussion will be facilitated with video clips from the video – physics of car crash and computer simulations of automobile safety features.
4. Students will also be assigned a homework assignment which requires them to consolidate their ideas and understanding on any three safety features ( assigned) and present one of it to class.Phase 3: Kindling the Discussion5. Students will use their notes and the Questioning Cube to answer and have small group discussions. 6. In whole group, students will participate in a discussion driven by the following questions:
Pros and cons of airbags
How safety rating impacts car buying
Working of truck escape ramps
Reducing impact force in collisionsPhase 4: Synthesis Activity7. Students will be divided into groups of three . Each group will appoint a recorder to record all computations neatly, an insurance agent who will collect all the facts and organize the information and a presenter who will present the case and argue in favor of their client. Each group will work on the Accident reconstruction Challenge by applying the principles they have learnt to solve the problem. On completing the reconstruction, each group may take the side of either of the parties involved and present the case in favor of their client with supporting arguments. 8. Summarizing Activity Problem design : Design a problem that integrates as many concepts as you can in this unit into a situation that involves a sport. Make sure your numbers are realistic and you have just sufficient data to solve the problem. Solve your problem and show the method.
Anchor Text(s): Wilson & Buffa – Physics textbook
Physics of car crashes – video to be used in discussionHandouts:Handout 1: Conservation of Momentum – worksheetHandout 2: Accident Reconstruction Challenge Handout 3: Questioning Cube