Tap a card to flip it. Each card stays open for 8 seconds, then flips back. You can open any card as many times as you like — but only one at a time.
Matching Practice
Tap a term on the left, then tap its matching definition on the right. Correct matches turn green. (1 point each)
Terms
Definitions
Section 2
Newton's First Law: Inertia & Friction
The Law of Inertia: An object at rest stays at rest, and an object in motion stays in motion at a constant velocity, unless acted on by an unbalanced (net) force.
Friction Investigation
The puck is launched at the same speed every time — the only thing you change is the surface. Run each surface, watch how far the puck slides before friction stops it, then record the stopping distance.
Distance: 0.0 m
Data Table: Stopping Distance by Surface
Record the stopping distance for each surface. Completing all four = 4 points.
Surface
Stopping Distance (m)
Analyze. Sum up your data. In 2–3 sentences, describe the relationship between how much friction a surface has and how far the puck slides — and use your stopping-distance numbers as evidence.
As friction increases, the distance…My data shows… because…
Reading: Why Seatbelts Save Lives
Imagine riding in a car traveling 50 kilometers per hour. Your whole body is moving at that same speed. When the driver suddenly slams on the brakes, the car stops — but your body still wants to keep moving forward at 50 kilometers per hour. This tendency to keep moving is called inertia.
A seatbelt applies a backward force across your chest and hips. That unbalanced force is what actually stops your body, instead of the dashboard or windshield stopping it. Airbags work the same way, spreading the stopping force over a larger area and a longer time so the force on any one part of your body is smaller. Headrests stop your head from snapping backward when a car is hit from behind. Every safety feature in a car is really a tool for applying a controlled force to overcome the inertia of a passenger.
A. Fill in the blank.
When a car stops suddenly, your body keeps moving forward because of .
B. Tap the words in order to build a correct sentence. Correct words turn green.
C. Expand this bare-bones sentence into a detailed one.
The passenger lurched forward.
When / Where?Why / How?
Check Your Understanding
Section 3
Newton's Second Law: F = ma
The acceleration of an object depends on the net force acting on it and its mass.
Net Force = mass × acceleration → F = m · a
Units: Force in newtons (N), mass in kilograms (kg), acceleration in m/s².
F = ma Cart Simulator
Adjust the force and mass. Acceleration is calculated live, and the cart speeds up at that rate. You will use this simulator to collect data for the two investigations below.
Acceleration = 6.0 m/s²
Investigation A — Vary the Force (mass held at 2 kg)
Set Mass = 2 kg on the simulator.
For each row, set the Force shown, then tap Capture to record the acceleration.
Force (N)
Mass (kg)
Acceleration (m/s²)
Calc. Using Graph A, calculate the slope between the first point (2 N, 1 m/s²) and the last point (10 N, 5 m/s²).
Slope = change in acceleration ÷ change in force.
Slope = (m/s²)/N
Investigation B — Vary the Mass (force held at 12 N)
Set Force = 12 N on the simulator.
For each row, set the Mass shown, then tap Capture to record the acceleration.
Force (N)
Mass (kg)
Acceleration (m/s²)
Calc. For ANY row in Table B, multiply mass × acceleration. What value do you get every time?
mass × acceleration = N
Check Your Understanding
Section 4
Net Force: Combining Forces
Net force is the single force that results when all forces on an object are combined. Forces in the same direction add together; forces in opposite directions subtract. When the net force is zero, the forces are balanced and motion does not change.
Worked Example
A box is pushed to the right with 30 N while friction pushes left with 12 N.
Net force = 30 N − 12 N = 18 N to the right. Because the net force is not zero, the box accelerates in that direction.
A. Expand this bare-bones sentence into a detailed one.
The forces were balanced.
When / Where?Why / How?
Check Your Understanding
Section 5
Newton's Third Law: Action & Reaction
For every action there is an equal and opposite reaction. When object A pushes on object B, object B pushes back on object A with the same size force in the opposite direction. The two forces act on different objects.
Balloon Rocket Investigation
Set the thrust, release the balloon, and a timer measures how long it takes to cross the string. Run each thrust setting and record the crossing time.
Time to cross: 0.0 s
Data Table: Thrust vs Crossing Time
Record the crossing time for each thrust setting. Completing all five = 4 points.
Thrust Setting
Time to Cross (s)
Reading: How a Rocket Reaches Space
A rocket carries fuel that burns inside its engines. The burning fuel creates hot gas that is forced out of the bottom of the rocket at tremendous speed. This downward push of gas is the action force.
According to Newton's third law, the escaping gas pushes back on the rocket with an equal force in the opposite direction. This upward reaction force is called thrust, and it is what lifts the rocket off the launch pad. A rocket does not need air to push against — it works even better in the vacuum of space, because there is no air resistance slowing it down. The same principle explains why a swimmer who pushes water backward glides forward, and why a balloon zips across a room when you let it go.
A. Fill in the blank.
A rocket moves forward because the exhaust gases are pushed .
B. Tap the words in order to build a correct sentence. Correct words turn green.
Check Your Understanding
Section 6
Quiz Challenge
Five questions are drawn at random from a large question bank. Score 60% or higher to unlock your Grade Report. You may retry as many times as you like — each retry gives a fresh set of questions.
Not yet attempted.
Section 7
Grade Report
Pass the Quiz Challenge (60% or higher) to unlock your full Grade Report and printable summary.