Collision Course Visual Guide Collision Course Visual Guide
Physics in Action: Momentum & Forces
1. Newton's 3rd Law: Action & Reaction
For every action force , there is an equal and opposite reaction force .
"If Car A hits Car B with 500 N of force, Car B hits Car A back with exactly 500 N."
Car A
Equal Forces
Car B
2. Collision Types: Does the math change?
Elastic (Bounce)
The math stays separate!
(m1 × v1) + (m2 × v2)
Objects hit and bounce. They still have their own separate mass and velocity .
Inelastic (Stick)
The math combines!
(m1 + m2) × v_combined
Objects hit and lock. They become one single mass moving with one velocity.
3. The Golden Rule of Momentum
Total Momentum BEFORE = Total Momentum AFTER
It doesn't matter if they bounce, stick, or explode. The total units of momentum in the system NEVER change!
Before
50 + 50 = 100
After (Stick)
100
After (Bounce)
80 + 20 = 100
Unit
kg · m/s
Vector
Speed + Direction
Force
Newtons (N)
Crash Lab Worksheet Crash Lab Worksheet
Objective 01: Newton's 3rd Law
Name: __________________________
Date: __________________________
01 The Action/Reaction Rule
Scenario: A large truck hits a tiny parked car.
1. If the truck hits the car with 10,000 N of force, how much force does the car hit back with? In what direction?
02 Your Turn: Grocery Store Crash
Describe a collision between two objects in a supermarket (e.g. carts hitting, a jar falling on the floor). Identify the Action and Reaction forces.
Collision Description:
Action Force (Object A on B):
Reaction Force (Object B on A):
03 Challenge: The Asteroid Strike
"A massive asteroid hits a small satellite. The satellite is crushed, but the asteroid doesn't even slow down."
TRUE or FALSE: The asteroid hit with MORE force than the satellite hit back? Explain your logic using Newton's 3rd Law.
Crash Lab Worksheet
Objective 02: Calculating Momentum
Formula: p = m × v
Momentum (p)
Mass in Motion
p = m × v
1. A 60 kg skateboarder moving at 5 m/s. Calculate momentum.
Show Math
Answer: kg·m/s
02 Momentum Challenge
A Bowling Ball (10 kg at 2 m/s) has 20 units of momentum. How fast must a light 2 kg ball travel to match that momentum?
Math logic: (2 kg × ? = 20)
Required Velocity:
_________ m/s
03 Your Scenario
Create your own problem using any mass and velocity.
Write word problem here:
Math Box
Final Answer:
Crash Lab Worksheet
Objective 03: Elastic Vs. Inelastic
Collision Types
Elastic
Bouncing Apart
Separate before, separate after.
Inelastic
Sticking Together
Separate before, joined after.
01 Which is it?
1. Two cars crash and bumpers lock together.
Elastic
Inelastic
2. A rubber bouncy ball hits a wall and jumps back.
Elastic
Inelastic
02 Challenge: Reality Check
A car hits a wall at 30 mph. It doesn't stick forever, but it also doesn't bounce like a rubber ball.
What happens to the car's SHAPE and ENERGY in this collision?
03 Massive Changes
Masses combine! If a 1,000 kg Car hits a 1,500 kg Truck and they stick, what is the total mass of the wreckage?
kg
04 Visual Sketches
Sketch an Elastic hit here
Crash Lab Worksheet
Objective 04: Conservation Math
Predictive Logic
The Golden Rule
Total Momentum Before = After
01 Predictive Math: Train Coupling
Scenario: A 10,000 kg Train moving at 4 m/s hits a parked 10,000 kg Car. They stick.
A) Momentum BEFORE (10,000 × 4):
B) Total Momentum AFTER they stick:
C) New Combined Mass (Total stuff):
New Speed?
Is the combined wreck:
FASTER
SLOWER
02 Design Your Own Saved System
Before: (Objects/Movement)
Total Momentum BEFORE:
After: (The Result)
Check: Do BEFORE and AFTER totals match?
Engineer Logic
Why is it important to know that Total Momentum is always the same, whether cars bounce or stick?
Crash Lab Answer Key Answer Key
Objective 01: Newton's 3rd Law
Teacher Resource
01 Action/Reaction Pairs
10,000 N
Direction: Opposite (Backward against the truck).
02 Grocery Store Example:
Example: Cart A hits Cart B.Action: Cart A hits Cart B forward.Reaction: Cart B hits Cart A backward with equal force.
03 Challenge: The Asteroid Strike
"FALSE. They hit each other with the EXACT SAME force. The satellite is destroyed because its mass is too small to resist the acceleration change, while the asteroid's massive body resists visible damage."
Answer Key
Objective 02: Calculating Momentum
Teacher Resource
01 Skateboarder (60 × 5)
300 kg·m/s
02 Challenge: The Match-Up
Velocity: 10 m/s
Logic: (2 kg × 10 m/s = 20 kg·m/s). The 5x lighter object must travel 5x faster.
03 Student Creation Note:
Check for p = m × v multiplication. Ensure students included units (kg·m/s).
Answer Key
Objective 03: Elastic Vs. Inelastic
Teacher Resource
01-1. Bumpers locking
INELASTIC
01-2. Bouncy ball hits wall
ELASTIC
02 Challenge: Reality Check
"The car's shape is permanently changed (crumpled). Kinetic energy is converted into sound, heat, and the mechanical work of bending metal."
03 Total mass?
2,500 kg
04 Bounce apart?
NO. Bouncing = Separation.
Answer Key
Objective 04: Conservation Math
Teacher Resource
01 Predictive Math Solutions:
A) Engine Momentum:
B) Total After:
C) Combined Mass:
D) NEW SPEED:
Engineer Logic Summary:
"Designing cars to crumple (inelastic-ish) spreads the momentum transfer over more TIME. This reduces the peak force on passengers. Total momentum is conserved, but human risk is minimized."
Collision Course Teacher Guide Collision Course
Teacher Facilitation Guide
Objectives
Differentiate between Elastic (bouncing) and Inelastic (sticking) collisions.
Calculate momentum (p = mv ) with simple multiplication.
Apply Conservation of Momentum to both collision types.
Discussion Hook
"If you throw a piece of clay at a wall, it sticks. If you throw a tennis ball, it bounces. Which one transfers more momentum?"
The Answer: The bouncing ball! Bouncing involves a larger change in velocity (going forward to going backward), which requires a larger force and momentum transfer.
Inelastic Insight
In 9th grade, we focus on Momentum Conservation . Even if energy is "lost" to heat or sound (which happens in inelastic hits), the Total Momentum of the system remains unchanged.
Suggested Pacing
10 MIN
Visual Guide
10 MIN
Sticky Demo
20 MIN
Worksheet
10 MIN
Debrief
Collision Momentum Slides Collision Physics
Visualizing Momentum Transfer
Step 1: Before the Hit
Truck Momentum (p )
2,000 kg × 10 m/s =
Small Car Momentum (p )
1,000 kg × 5 m/s =
Total System Momentum 25,000 kg·m/s
Step 2: The Impact
Truck
Force on Car
Force on Truck
Equal & Opposite Forces
Car
Momentum is exchanged. Whatever one loses, the other gains.
Step 3A: Elastic (Bouncing)
Separated Math
12,500 + 12,500
(Objects remain separate)
Math uses m1 and m2 separately.
Each object keeps its own velocity.
Elastic Total 25,000 kg·m/s
Step 3B: Inelastic (Sticking)
Combined Math
(m1 + m2) × v
(Objects move as one)
Math adds m1 + m2 together.
Both objects share one velocity .
Inelastic Total 25,000 kg·m/s
The Math Secret
The Total Momentum math never changes.
The Golden Rule
Before = After
Sticky or Bouncy... the total stays the same.
