Physics Power Slides Physics Power
Forces & Motion • NC EOG Mastery
Standard: 8.P.1
The Language of Motion
Defining how things move.
Speed
The distance an object travels per unit of time.
\( s = \frac{d}{t} \)
Velocity
Speed in a specific direction .
Example: 55 mph North.
Acceleration
Any change in velocity (speeding up, slowing down, or changing direction ).
1
Law of Inertia
"An object at rest stays at rest, and an object in motion stays in motion unless acted upon by an unbalanced force ."
What is Inertia?
The resistance of an object to change its motion. More mass = More inertia!
Harder to stop a truck than a bicycle.
Why? The truck has more inertia (mass).
2
The Formula for Force
\[ F = m \times a \]
Force (F)
Measured in Newtons (N)
Mass (m)
Measured in Kilograms (kg)
Acceleration (a)
Measured in \(m/s^2\)
"The acceleration of an object depends on the mass of the object and the amount of force applied."
3
Action & Reaction
"Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first."
Rocket Launch
Action: Gas pushes down. Reaction: Rocket pushes up.
Walking
Action: You push ground back. Reaction: Ground pushes you forward.
Vector Visuals
Free-Body Diagrams
We use arrows to show Magnitude (strength) and Direction of forces.
Arrows point AWAY from object
Longer arrow = Stronger force
Net Force = Combination of all forces
OBJECT
Normal Force
Gravity
Applied
Friction
Graphing the EOG Way
Distance-Time Graph
Distance
Time
Slope = Speed
Flat line = Stopped
Speed-Time Graph
Speed
Time
Slope = Acceleration
Flat line = Constant Speed
Quick Check!
A 50 kg boulder is pushed with 200 N of force. What is the boulder's acceleration?
Knowns:
Formula:
Newton's Blueprint Worksheet Blueprint Series
Newton's Blueprint
NCSCOS 8.P.1: Forces, Motion, and Newton's Laws
Name:
Date: _________ Class: _________
Part 1: Force Calculations
Use \(F = m \times a\) to solve. Round to the nearest tenth. Include units!
1. A 1,200 kg car accelerates at a rate of 3.5 \(m/s^2\). What is the net force acting on the car?
2. A soccer ball is kicked with 25 N of force and accelerates at 50 \(m/s^2\). What is the mass of the ball?
Part 2: Vector Visualization
Calculate the net force and direction for each diagram.
15 N
35 N
Net Force: ________ Direction: ________
10 N
10 N
Net Force: ________ Motion: ________
Newton's Law Matching
Scenario A
A magician pulls a tablecloth from under a set of dishes. The dishes stay in place while the cloth moves away.
Which Law? (1, 2, or 3)
Scenario B
A canoeist pushes their paddle backward against the water to move the boat forward across the lake.
Which Law? (1, 2, or 3)
Scenario C
An empty shopping cart is much easier to push and turn than a shopping cart filled with groceries.
Which Law? (1, 2, or 3)
Part 3: Decoding the Data
4. Look at the Distance-Time graph below. Describe the motion of the object in each segment.
A
B
C
Segment A: ___________________________________Segment B: ___________________________________Segment C: ___________________________________
EOG Tip
If the line is flat on a Distance-Time graph, the object is at rest. If the line is flat on a Speed-Time graph, the object is moving at a constant speed!
5. Why would an astronaut weigh less on the moon than on Earth, even though their mass stays the same?
Advanced Blueprints
Deep Dive into Force Interactions
6. The Tug-of-War Challenge
Team Alpha and Team Beta are in a tug-of-war. Team Alpha pulls with a force of 450 N to the left. Team Beta pulls with a force of 425 N to the right. The rope and both teams have a combined mass of 600 kg.
A) Draw the free-body diagram for the system below:
DRAW ARROWS AND LABEL MAGNITUDES
B) Calculate the Net Force (\(F_{net}\)):
EOG Sprint Quiz EOG Sprint Quiz
Standard 8.P.1 • Force & Motion Mastery
Time Limit: 20 MIN
Name: ________________________ Date: ___________
Score: ____ / 10
A student pulls a wooden block across a table with a constant speed of 2 m/s. Which statement best describes the forces acting on the block?
The forces are unbalanced, and the net force is greater than zero.
The forces are balanced, and the net force is zero.
The force of friction is greater than the pulling force.
Gravity is the only force acting on the block.
An object has a mass of 10 kg. If a net force of 50 N is applied to the object, what will be its acceleration?
0.2 \(m/s^2\)
5 \(m/s^2\)
60 \(m/s^2\)
500 \(m/s^2\)
Which of the following graphs represents an object moving at a constant speed?
Graph A
Dist vs Time
Graph B
Dist vs Time
Graph C
Speed vs Time
Graph D
Dist vs Time
Graph A
Graph B
Graph C
Graph D
A person steps out of a boat onto a dock. As the person moves forward, the boat moves backward. Which of Newton's Laws explains this occurrence?
Newton's 1st Law (Law of Inertia)
Newton's 2nd Law (Law of Force and Acceleration)
Newton's 3rd Law (Law of Action and Reaction)
The Law of Universal Gravitation
Why does a bowling ball require more force to move than a tennis ball when both are at rest?
The bowling ball has more friction than the tennis ball.
The tennis ball has more inertia than the bowling ball.
The bowling ball has more mass, giving it more inertia.
The tennis ball is influenced by gravity more than the bowling ball.
Four toy cars are pushed with different amounts of force. According to the table below, which car will have the greatest acceleration?
Toy Car Mass (kg) Force Applied (N) Car W 2.0 10.0 Car X
Physics Power Teacher Guide Teacher Guide
Physics Power: Force & Motion Mastery
8th Grade Science
NCSCOS 8.P.1
Lesson Objectives
Students will identify and explain Newton’s Three Laws of Motion .
Students will calculate Force, Mass, and Acceleration using \(F=ma\).
Students will interpret Distance-Time and Speed-Time graphs.
Students will analyze Free-Body Diagrams to determine net force and motion direction.
Common Misconceptions
Misconception: "Constant speed means there is a force acting on the object."
Reality: Constant speed (zero acceleration) means the net force is ZERO. Forces are balanced.
Misconception: "Mass and Weight are the same thing."
Reality: Mass is the amount of matter (constant). Weight is the force of gravity (changes by location).
Facilitation Tips
The Slide Deck
Use the "Action/Reaction" slide to do a quick "push against the wall" demonstration. If you push the wall, the wall pushes you!
Calculating Force
Encourage students to draw the "Force Triangle" on their scratch paper immediately when the EOG begins.
EOG Strategy
Many 8.P.1 items on the EOG focus on interpreting data tables . Stress the relationship: if mass is constant, higher force MUST equal higher acceleration.
Master Answer Key
Newton's Blueprint Worksheet
1. Force Calculation: 1,200 kg × 3.5 \(m/s^2\) = 4,200 N
2. Mass Calculation: 25 N / 50 \(m/s^2\) = 0.5 kg
3. Vectors: Net Force = 20 N; Direction = Right. Next: Net Force = 0 N; Motion = Constant Speed or Stopped.
4. Scenarios: A = Law 1 (Inertia), B = Law 3 (Action/Reaction), C = Law 2 (\(F=ma\)).
5. Segment Analysis: A = Accelerating/Constant Speed away, B = Stopped, C = Returning at constant speed.
6. Tug-of-War: \(F_{net} = 25 N\) Left; Accel = \(25 / 600 \approx 0.04 m/s^2\).
EOG Sprint Quiz
1 B (Balanced forces = Constant speed)
2 B (50 / 10 = 5 \(m/s^2\))
3 A (Diagonal line on D-T graph)
4 C (Action/Reaction)
5 C (More mass = More inertia)
6 X (20/2 = 10, others are lower)
