Mechanics
Force lab
Watch the box accelerate steadily from rest under one constant applied force — a = F/m.
Force lab — interactive Mechanics simulation. Watch the box accelerate steadily from rest under one constant applied force — a = F/m. Free browser-based virtual physics lab with live SI measurements and a guided tutorial.
Newton's second law
A net force on an object produces acceleration: F = ma. Greater force or smaller mass means larger acceleration.
Newton's second law links force, mass, and acceleration. When a single horizontal push acts on a block on a frictionless floor, the net force equals that push. The block accelerates steadily from rest in the direction of the net force.
- F = ma
- a = F / m
Investigation brief
Plan the question before you open the lab
The brief mirrors the prerendered page: driving question, competing predictions, variable roles, governing laws, setup, analysis and extension prompts remain visible and in this order.
Driving question
You push a box across a frictionless floor with a steady force. If you push a heavier box with that same force, does it speed up faster, slower, or at the same rate as a lighter box?
Predictions to weigh
- The heavier box accelerates faster
- Both boxes accelerate at the same rate
- The heavier box accelerates slower
Variable roles
What you set:
- Mass (kg)
- Applied Force (N)
What you measure:
- Speed at t = 1 s (m/s)
- Momentum at t = 1 s (kg·m/s)
How the investigation runs
- Open the Force Lab preset. A single box sits at rest on a frictionless floor with one constant force pushing it forward.
- Confirm the speed probe is attached to the box, then check the box's mass and the applied force's strength in the Properties panel panel.
- For each row below, set the box's mass and the force's strength in the Properties panel to match, run the simulation for exactly 1 second (60 frames), and read the probe's speed.
Governing equation
Newton's Second Law — F = m·a
The net force on an object equals its mass times its acceleration. Here a single constant force accelerates the box from rest, so the speed measured after a fixed time reveals the acceleration that force produced.
Momentum — p = m·v
Momentum is mass times velocity. Every trial starts from rest, so the momentum at the 1-second mark shows how much motion the same push builds up in boxes of different mass.
What the printable worksheet asks students to work out
- For each row, divide the applied force by the mass. How does that value compare to the speed you measured after 1 second? What quantity have you just calculated?
- Compare rows 1 and 3 (same force, different mass). How much did doubling the mass change the resulting speed after the same 1-second push?
Where this shows up beyond the lab
- This floor is frictionless. Predict how your speed readings would change if a small constant friction force also acted on the box. Would dividing the applied force by mass alone still predict the resulting acceleration?
- A shopping cart and a loaded delivery truck can both be pushed by an engine producing the same force. Use your data to explain why they don't speed up at the same rate.
- AP Physics 1 — Unit 2: Force and Translational Dynamics
- AP Physics C: Mechanics — Unit 2: Force and Translational Dynamics
- IB Physics — A.2 Forces and momentum
- General High School Physics — Forces & Newton's laws
- NGSS High School Physics — Forces and Newton's second law
- Middle School Physical Science — Force, mass, and motion
- Welcome to the force lab
- Select the block
- Press Play
- Steady acceleration
- Open the data
- You did it!
Open the interactive simulation to build the scene, press Play, and explore with live measurements and a guided tutorial.