Goal: Students will be introduced to the relationships between force, time, impulse, and linear momentum via calculations, data analysis, designing experiments, and making predictions. Students will learn how to use new models and representations to illustrate the law of conservation of linear momentum of objects and systems while gaining proficiency using previously studied representations. Using the law of conservation of linear momentum to analyze physical situations provides students with a more complete picture of forces and opportunities to revisit misconceptions surrounding Newton’s third law. Students will also have the opportunity to make connections between momentum and kinetic energy of objects or systems and see under what conditions these quantities remain constant.
To access the main folder and get class notes and additional practice problems per each topic below click the following link:
AP Physics 1-Unit 4-Linear Momentum
(time to complete all WebAssign Problems approximately 6hr 35min)
**You will take 1 test during this unit.**
Learning Objective:
-Describe the linear momentum of an object or system.
Essential Knowledge:
-Linear momentum is an object tendency to want to stay in motion.
-Momentum is a vector quantity and has the same direction as the velocity.
-Momentum can be used to analyze collisions and explosions.
-A collision is a model for an interaction where the forces exerted between the involved objects in the system are much larger than the net external force exerted on those objects during the interaction.
-As only the initial and final states of a collision are analyzed, the object model may be used to analyze collisions.
-An explosion is a model for an interaction in which forces internal to the system move objects within that system apart.
Skills:
-Create qualitative sketches of graphs that represent features of a model or the behavior of a physical system.
-Calculate or estimate an unknown quantity with units from known quantities, by selecting and following a logical computational pathway.
-Compare physical quantities between two or more scenarios or at different times and locations in a single scenario.
-Apply an appropriate law, definition, theoretical relationship, or model to make a claim.
Read & Take Notes on Sections: 6.1, 6.2, 6.3
WebAssign: Ch 6 - 1, 12, 17, 21, 23, 29
Learning Objective:
-Describe the impulse delivered to an object or system.
-Describe the relationship between the impulse exerted on an object or a system and the change in momentum of the object or system.
Essential Knowledge:
-The rate of change of momentum is equal to the net external force exerted on an object or system.
-Impulse is defined as the product of the average force exerted on a system and the time interval during which that force is exerted on the system.
-Impulse is a vector quantity and has the same direction as the net force exerted on the system.
-The impulse delivered to a system by a net external force is equal to the area under the curve of a graph of the net external force exerted on the system as a function of time.
-The net external force exerted on a system is equal to the slope of a graph of the momentum of the system as a function of time.
-Change in momentum is the difference between a system’s final momentum and its initial momentum.
-The impulse–momentum theorem relates the impulse exerted on a system and the system’s change in momentum.
-Newton’s second law of motion is a direct result of the impulse–momentum theorem applied to systems with constant mass.
Skills:
-Create quantitative graphs with appropriate scales and units, including plotting data.
-Derive a symbolic expression from known quantities by selecting and following a logical mathematical pathway.
-Predict new values or factors of change of physical quantities using functional dependence between variables.
-Create experimental procedures that are appropriate for a given scientific question.
-Justify or support a claim using evidence from experimental data, physical representations, or physical principles or laws.
Read & Take Notes on Sections: 6.1, 6.2, 6.3
WebAssign: Ch 6 - 1, 12, 17, 21, 23, 29
Learning Objective:
-Describe the behavior of a system using conservation of linear momentum.
-Describe how the selection of a system determines whether the momentum of that system changes.
Essential Knowledge:
-A collection of objects with individual momenta can be described as one system with one center-of-mass velocity.
-For a collection of objects, the velocity of a system’s center of mass can be calculated.
-The velocity of a system’s center of mass is constant in the absence of a net external force.
-The total momentum of a system is the sum of the momenta of the system’s constituent parts.
-In the absence of net external forces, any change to the momentum of an object within a system must be balanced by an equivalent and opposite change of momentum elsewhere within the system. Any change to the momentum of a system is due to a transfer of momentum between the system and its surroundings.
-Momentum is conserved in all interactions.
-If the net external force on the selected system is zero, the total momentum of the system is constant.
-If the net external force on the selected system is nonzero, momentum is transferred between the system and the environment.
-The impulse exerted by one object on a second object is equal and opposite to the impulse exerted by the second object on the first. This is a direct result of Newton’s third law.
-A system may be selected so that the total momentum of that system is constant.
-If the total momentum of a system changes, that change will be equivalent to the impulse exerted on the system.
-Correct application of conservation of momentum can be used to determine the velocity of a system immediately before and immediately after collisions or explosions.
Skills:
-Create diagrams, tables, charts, or schematics to represent physical situations.
-Derive a symbolic expression from known quantities by selecting and following a logical mathematical pathway.
-Predict new values or factors of change of physical quantities using functional dependence between variables.
-Justify or support a claim using evidence from experimental data, physical representations, or physical principles or laws.
Read & Take Notes on Sections: 6.1, 6.2, 6.3, 6.4
WebAssign: Ch 6 - 1, 12, 17, 21, 23, 29, 32, 33, 39, 40, 42, 47, 49, 51, 53
**Note**
-AP Physics 1 includes a quantitative and qualitative treatment of conservation of momentum in one dimension and a semiquantitative treatment of conservation of momentum in two dimensions. Exam questions involving solution of simultaneous equations are not included in AP Physics 1, but the AP Physics 1 Exam may include questions that assess whether students can set up the equations properly and reason about how changing a given mass, speed, or angle would affect other quantities.
Learning Objective:
-Describe whether an interaction between objects is elastic or inelastic.
Essential Knowledge:
-An elastic collision between objects is one in which the initial kinetic energy of the system is equal to the final kinetic energy of the system.
-In an elastic collision, the final kinetic energies of each of the objects within the system may be different from their initial kinetic energies.
-An inelastic collision between objects is one in which the total kinetic energy of the system decreases.
-In an inelastic collision, some of the initial kinetic energy is not restored to kinetic energy but is transformed by nonconservative forces into other forms of energy.
-In a perfectly inelastic collision, the objects stick together and move with the same velocity after the collision.
Skills:
-Create quantitative graphs with appropriate scales and units, including plotting data.
-Derive a symbolic expression from known quantities by selecting and following a logical mathematical pathway.
-Compare physical quantities between two or more scenarios or at different times and locations in a single scenario.
-Create experimental procedures that are appropriate for a given scientific question.
-Apply an appropriate law, definition, theoretical relationship, or model to make a claim.
Read & Take Notes on Sections: 6.1, 6.2, 6.3
WebAssign: Ch 6 - 1, 12, 17, 21, 23, 29 & Ch6 AP Multiple-Choice Review Questions
Online Demo: 2-D Collision Simulation
Test 6