Using PASCO Force Sensors to Study Impulse and Momentum

Impulse and momentum are central ideas in mechanics, linking force and motion in real, measurable ways. Using PASCO force sensors, students can record how forces change during a collision and see how impulse equals the change in momentum.

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The Experiment

A PASCO force sensor is attached to a dynamics cart or collision block on a track. When the cart collides with a spring bumper or another cart, the sensor records the force-time graph.

Students can then calculate the impulse by finding the area under the force-time curve:

$$\text{Impulse} = \int F\,dt = \Delta p = m(v - u)$$

where $m$ is the mass of the cart, and $u$ and $v$ are the initial and final velocities.

The data show that even though force varies during the collision, the total impulse equals the change in momentum.

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The Science

Impulse describes how a force acting over a time interval changes momentum.

• A large force acting briefly can have the same effect as a small force acting for longer.

• Momentum is always conserved when no external forces act — an essential principle in both linear and two-dimensional collisions.

By comparing different materials, bumpers, or collision speeds, students can see how impulse spreads over time to reduce peak force — the same principle used in crumple zones and safety equipment.

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Skills Highlight

• Using sensors to record time-resolved force data

• Calculating impulse from graphs and comparing it with measured momentum change

• Interpreting conservation of momentum in real systems

• Relating physics to real-world safety design and engineering

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Why It Works in Teaching

PASCO force sensors transform an invisible concept into a measurable one. Students don’t just accept that impulse equals the change in momentum — they prove it by analysing real data and connecting mathematical models to physical events.