## Lesson 9: Collisions

## Overview:

Collisions occur all the time in our lives, here we will study the different types of collisions, and focus on the ideal cases which are known as perfectly elastic and perfectly inelastic.

## Curriculum Expectations:

**Overall Expectations:**

**C2.**Investigate, in qualitative and quantitative terms, through laboratory inquiry or computer simulation, the relationship between the laws of conservation of energy and conservation of momentum, and solve related problems.

**C3.**Demonstrate an understanding of work, energy, momentum, and the laws of conservation of energy and conservation of momentum, in one and two dimensions.

**Specific Expectations:**

**C1.1**Analyze, with reference to the principles of energy and momentum, and propose practical

ways to improve, a technology or procedure that applies these principles (e.g., fireworks, rocket propulsion, protective equipment, forensic analysis of vehicle crashes, demolition of buildings).

**C2.1**Use appropriate terminology related to energy and momentum, including, but not limited to:

work, work–energy theorem, kinetic energy, gravitational potential energy, elastic potential energy, thermal energy, impulse, change in momentum–impulse theorem, elastic collision, and inelastic collision.

**C2.6**Analyze, in qualitative and quantitative terms, elastic and inelastic collisions in one and two dimensions, using the laws of conservation of momentum and conservation of energy, and solve related problems.

**C3.3**Distinguish between elastic and inelastic collisions.

## Success Criteria:

- What are the two types of collisions? How do we distinguish which of the two collisions occur?
- What is the conservation of kinetic energy? And in what type of collision does it hold true?
- Why is kinetic energy conserved during elastic collisions? Describe the energy transformations.
- Why is kinetic energy not conserved during inelastic collisions? Where does the energy go?
- During both elastic and inelastic collisions, what is conserved? What is not conserved?
- Compare and contrast perfectly elastic collisions vs. perfectly inelastic collisions.

## Time Allocation: 1 hour

## Learning A

ctivities:**Read**pages 233 - 238 from Nelson 5.3 and

**copy the sample problems**into your notes.

In the playlist below, video:

- Will show you how to solve a problem when a block slides down and sticks to another block on a semispherical bowl.
- Will show you how much energy can a bullet impart on a block of wood.

**Practice**

**question 1 on page 236.**

**Practice**

**questions 1, 2, and 3 on page 238.**

## Task:

**Solve**questions 2, 6, and 8 from Nelson 5.3 Review on page 239.

Complete the

**Momentum and Neutrino**assignment on Moodle.

*Optional Extension:*- Solve questions 4 and 5 on page 239.

## Reflect:

Can we ever make automobiles completely safe for humans? Use your knowledge of momentum and conservation of mechanical energy to answer this question.