Simply open index.html in any modern web browser. That's it! No installation needed.
Use the controls to set:
- Mass 1: Weight of the left object (in kg)
- Mass 2: Weight of the right object (in kg)
- Initial Velocity: Starting velocity (positive = Mass 1 moves down)
- Click Start to begin
- Click Pause to freeze
- Click Reset to restart
- Blue block (M₁): Mass 1 (left side)
- Red block (M₂): Mass 2 (right side)
- Green arrows (v): Velocity vectors
- Orange dashed arrows (a): Acceleration vectors
- Acceleration: How quickly velocity changes (m/s²)
- Current Velocity: Speed and direction of motion (m/s)
- Tension: Force in the rope (Newtons)
- Time: Elapsed simulation time (seconds)
Goal: Demonstrate that heavier mass accelerates down
- Set: m₁ = 2 kg, m₂ = 4 kg, v₀ = 0 m/s
- Result: M₂ accelerates downward at 3.27 m/s²
Goal: Show acceleration ≠ direction of motion
- Set: m₁ = 2 kg, m₂ = 3 kg, v₀ = -4 m/s
- Result: M₁ moves down initially, but acceleration points up!
- Watch: Eventually motion reverses to match acceleration
Goal: Demonstrate constant velocity with equal masses
- Set: m₁ = 3 kg, m₂ = 3 kg, v₀ = 2 m/s
- Result: Zero acceleration, constant velocity maintained
Goal: Show effect of large mass difference
- Set: m₁ = 1 kg, m₂ = 10 kg, v₀ = 0 m/s
- Result: Rapid acceleration (≈8 m/s²)
- Velocity = current speed and direction
- Acceleration = rate of change of velocity
- They can point in opposite directions!
The heavier mass creates a net force:
- If m₂ > m₁: system accelerates with m₂ going down
- If m₁ > m₂: system accelerates with m₁ going down
- If m₁ = m₂: zero net force, zero acceleration
The rope tension is always the same throughout (assuming massless rope):
- Tension is LESS than the weight of either mass
- Maximum tension occurs when masses are equal
- Formula: T = 2m₁m₂g/(m₁+m₂)
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Watch the arrows: Green (velocity) shows motion direction, orange (acceleration) shows which way velocity is changing
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Equal masses are special: When masses are equal, the system is in equilibrium (or constant motion)
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Initial velocity matters: The system can temporarily move "against" its acceleration
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Pause and observe: Use pause to examine the vectors at any moment
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Try extreme values: Experiment with very different masses or high initial velocities
Works best on:
- ✅ Chrome/Edge (Recommended)
- ✅ Firefox
- ✅ Safari
- ✅ Any modern mobile browser
This simulation works on tablets and phones:
- Tap controls to adjust values
- Pinch to zoom if needed
- Landscape orientation recommended
Q: Why does mass 1 move down when mass 2 is heavier? A: Because you set a negative initial velocity! Acceleration will eventually reverse the motion.
Q: Why doesn't anything move when masses are equal? A: With equal masses and zero initial velocity, there's no net force and no acceleration. Try adding an initial velocity!
Q: What does "frictionless pulley" mean? A: It means we ignore friction and the pulley's mass. Real pulleys would behave slightly differently.
Q: Can I use this for homework/projects? A: Yes! This is an educational tool. Use it to verify your calculations and understand the concepts.
- Experiment freely with different values
- Try to predict motion before clicking Start
- Verify calculations by hand and compare
- Share with classmates and friends
Happy Learning! 🎓
For more physics simulations, visit The Thinking Experiment