Motion and Energy Review Worksheet
NYSSLS Middle School Physical Science
Forces, Motion & Energy Review
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Date:
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MS-PS2-1 Newton's Third Law: Action-Reaction Pairs in Collisions
Part 1 of 4
Step-by-Step Concept Review: Newton's Third Law of Motion
1. Equal & Opposite Whenever Object A exerts a force on Object B, Object B exerts a force on Object A that is equal in magnitude and opposite in direction.
2. Two Different Objects Action-reaction forces never cancel out because they act on separate bodies (Force of A on B vs. Force of B on A).
3. Collision Dynamics Even if one object is much heavier, the contact forces during the collision are strictly identical in strength.
Phenomenon 1: Autonomous Docking Collision
During a low-Earth orbit test, a heavy supply capsule (\(m = 4{,}500\text{ kg}\)) collides at low speed with a lightweight orbital relay probe (\(m = 300\text{ kg}\)). Both craft are fitted with front-facing telemetry sensors that measure contact forces during the impact.
1 Identify and compare the collision forces exerted by the two spacecraft:
a) State the force exerted by the capsule on the probe:
b) Compare their force magnitudes (circle one):
Capsule is Greater Strictly Equal Probe is Greater
c) Explain why the lightweight probe experiences a much greater change in motion (acceleration) than the capsule even though the forces are equal:
2 Design Solution (MS-PS2-1): Reducing Peak Collision Forces
Engineers need to install an impact-absorption system between the craft to prevent delicate instrumentation from breaking during docking.
a) Describe how modifying collision duration (e.g., using spring-dampers or honeycombed crush materials) alters the peak impact force:
b) Complete a sketch or labeled diagram showing the two colliding surfaces with Third Law force vectors labeled with correct directions:
Standard MS-PS2-1 • Newton's Third Law & Collision Systems Page 1 of 4
MS-PS2-2 Net Force, Mass, and Motion Investigation Planning
Part 2 of 4
Step-by-Step Concept Review: Newton's Second Law & Experimental Design
1. Sum of Forces (\(F_{net}\)) Balanced forces (\(F_{net} = 0\)) cause zero change in motion (constant speed or at rest). Unbalanced forces (\(F_{net} \neq 0\)) cause acceleration.
2. Mass & Inertia Mass is the measure of an object's inertia. For a constant net force, acceleration is inversely proportional to mass (\(a \propto \frac{1}{m}\)).
3. Fair Test Design To test the effect of mass, keep force constant. To test the effect of force, keep mass constant. Measure rate of speed change (\(\Delta v / \Delta t\)).
Phenomenon 2: The Maglev Test Track Sled
A transportation laboratory tests magnetic levitation cargo sleds along a zero-friction track. Sled A has a total mass of \(200\text{ kg}\), while Sled B is loaded with freight to reach \(600\text{ kg}\). Both are propelled forward by electromagnets that exert a constant horizontal forward force of \(1{,}200\text{ N}\). A braking wind gust exerts a backward drag of \(400\text{ N}\).
3 Net Force and Motion Analysis
a) Calculate the net horizontal force on the sled:
Show calculation: \(F_{forward} - F_{drag}\)
b) Compare acceleration rates:
Which sled will accelerate 3 times faster? Justify using mass:
4 Investigation Planning Protocol (MS-PS2-2)
You are tasked with planning a classroom laboratory investigation to provide evidence that changing an object's mass alters its acceleration when the applied net force is kept constant.
| Variable Type |
Identify Specific Factor in Investigation |
| Independent Variable |
|
| Dependent Variable |
|
| Two Controlled Variables |
|
Write a 3-step experimental procedure and state which tool you will use to measure motion change (e.g., photogates, motion sensors, or stopwatches):
Standard MS-PS2-2 • Forces, Mass, & Motion Experimental Design Page 2 of 4
MS-PS3-1 Kinetic Energy: Interpreting Graphical Displays of Mass & Speed
Part 3 of 4
Step-by-Step Concept Review: Kinetic Energy Relationships (\(KE = \frac{1}{2}mv^2\))
Linear Relationship with Mass (\(KE \propto m\)) If speed is held constant:
- Doubling mass (\(2\times m\)) \(\rightarrow\) Doubles KE (\(2\times KE\))
- Graph of KE vs. Mass is a straight line through origin.
Non-Linear Relationship with Speed (\(KE \propto v^2\)) If mass is held constant:
- Doubling speed (\(2\times v\)) \(\rightarrow\) Quadruples KE (\(4\times KE\))
- Graph of KE vs. Speed curves upward parabolically.
Phenomenon 3: High-Speed Impact Barrier Testing
Automotive engineers tested robotic test carts striking an energy-measuring barrier. They recorded kinetic energy data while systematically varying either mass or impact speed.
Graph A: Constant Speed (\(10\text{ m/s}\)) Mass (kg) KE (kJ) Linear Relationship
Graph B: Constant Mass (\(500\text{ kg}\)) Speed (m/s) KE (kJ) Non-linear (Quadratic) Curve
| Trial |
Mass |
Speed |
KE |
| 1 |
500 kg |
10 m/s |
25 kJ |
| 2 |
1,000 kg |
10 m/s |
50 kJ |
| 3 |
500 kg |
20 m/s |
100 kJ |
| 4 |
500 kg |
30 m/s |
225 kJ |
5 Interpreting Graphical Data Displays (MS-PS3-1)
a) Compare Trials 1 and 2: How does doubling mass affect kinetic energy? Cite data from the table:
b) Compare Trials 1 and 3: How does doubling speed affect kinetic energy? Explain the shape of Graph B:
6 Predictive Proportional Reasoning
a) If a cart's speed increases from \(10\text{ m/s}\) to \(40\text{ m/s}\) (a \(4\times\) increase), by what factor will its kinetic energy increase?
b) A highway safety officer states: "Driving at 60 mph is twice as dangerous as 30 mph because kinetic energy doubles." Construct an argument using graphical evidence to refute this statement:
Standard MS-PS3-1 • Kinetic Energy, Mass, & Speed Graphical Relationships Page 3 of 4
INTEGRATED CHALLENGE Synthesizing MS-PS2-1, MS-PS2-2 & MS-PS3-1
Part 4 of 4
Capstoning Phenomenon: Autonomous Delivery Rover Emergency Stop
An urban sidewalk delivery rover (\(m = 40\text{ kg}\)) is travelling at \(6\text{ m/s}\) when its LiDAR detects a stationary concrete bollard directly ahead. The rover's emergency friction brake applies a constant backwards force of \(120\text{ N}\). If the rover fails to stop in time, it impacts the concrete bollard with its front bumper system.
7 Part A: Kinetic Energy Audit (MS-PS3-1)
a) Calculate the rover's initial kinetic energy at \(6\text{ m/s}\):
\(KE = \frac{1}{2} \cdot 40\text{ kg} \cdot (6\text{ m/s})^2\)
b) If the operator throttles speed down to \(3\text{ m/s}\) (half speed), what is the new KE?
Apply proportional reasoning:
8 Part B: Braking Force & Motion Change (MS-PS2-2)
a) Draw a labeled force arrow diagram showing all forces on the rover during braking:
b) If the rover is loaded with groceries doubling its mass to \(80\text{ kg}\), how will its deceleration rate change under the same \(120\text{ N}\) braking force?
9 Part C: Collision Engineering Solution (MS-PS2-1)
Suppose the rover strikes the stationary concrete bollard.
a) Apply Newton's Third Law: Compare the force the rover bumper exerts on the concrete bollard to the force the bollard exerts back on the rover bumper:
b) Design an engineering improvement for the rover's front bumper to minimize cargo damage during an impact. Explain the scientific principle behind why your design reduces damage:
Student Standard Mastery Self-Check
MS-PS2-1: 3rd Law Collisions MS-PS2-2: Net Force & Investigation MS-PS3-1: KE Graphs (Mass & Speed)
NYSSLS Physical Science Review • MS-PS2-1, MS-PS2-2, MS-PS3-1 Page 4 of 4
