Forward Velocity

Using the @pascoscientific smartcart with the motorised fan to explore how the angle of the force can affect the forward velocity, and comparing this to the mathematical model, to see if there is a correlation. It was spot on.

Exploring Force and Motion with an Angled Fan on a Trolley

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Physics comes alive when we turn everyday equipment into powerful demonstrations of fundamental laws. In this experiment, we mount a fan on a low-friction trolley and observe how varying the angle of the fan's thrust affects the trolley’s velocity and acceleration. It’s a brilliant way to visualise the components of force and how they influence motion in different directions.

Whether you’re a student learning Newton’s laws or a teacher looking for a fresh experiment to run in class, this setup is simple, scalable, and rich in learning opportunities.

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🧪 Experiment Overview: A Fan on a Moving Trolley

🛠 Equipment Needed:

• Dynamics trolley (preferably low-friction or on a track)

• Fan unit (with adjustable mounting angle)

• Inclined or flat track with motion sensor or Smart Cart

• Stopwatch or data logging system (e.g., PASCO Capstone)

• Protractor or angular scale for setting the fan angle

• Ruler or measuring tape

• Masses (optional, for further variation)

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🧭 Aim of the Experiment

To investigate how changing the angle of a fan's thrust affects the acceleration and velocity of a trolley moving along a track.

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🔍 Scientific Principle

The fan produces a thrust force at an angle $\theta$ to the direction of motion. This force can be resolved into two components:

• Horizontal force (Fₓ) = $F \cos\theta$ — this affects forward motion.

• Vertical force (Fᵧ) = $F \sin\theta$ — this may lift slightly or press the trolley down, affecting friction.

By changing the fan’s angle, we alter how much of the thrust is pushing the trolley forwards.

This is a practical example of vector decomposition and Newton’s Second Law:

$$F = ma$$

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🧪 Method: Step-by-Step

Part 1: Setup

1. Mount the fan securely on the trolley. Ensure the angle of thrust can be measured accurately.

2. Place the trolley at one end of a level track with a motion sensor or Smart Cart ready to record velocity or acceleration.

3. Record the mass of the trolley and fan combined.

Part 2: Measurements

4. Set the fan angle to 0° (fully horizontal). Turn on the fan and record the trolley's acceleration.

5. Repeat for several angles — e.g., 15°, 30°, 45°, 60°, and 75°.

6. Record data for each run, such as:

   • Time to travel a fixed distance

   • Acceleration (if using sensors)

   • Final velocity after a known time interval

Part 3: Analysis

7. Calculate the expected horizontal force component for each angle:

   $$F_x = F \cos\theta$$

   where $F$ is the total thrust force of the fan.

8. Compare predicted vs. actual acceleration using:

   $$a = \frac{F_x}{m}$$

9. Plot:

   • Angle vs. velocity

   • Angle vs. acceleration

   • Horizontal force vs. acceleration

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📊 Example Data Table

Fan Angle (°)	Time (s)	Distance (m)	Velocity (m/s)	Acceleration (m/s²)
0°	2.5	2.0	0.80	0.32
15°	2.7	2.0	0.74	0.27
30°	3.2	2.0	0.63	0.20
45°	4.1	2.0	0.49	0.12
60°	5.8	2.0	0.34	0.06

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🔁 Extensions and Variations

• Friction investigation: Try running the trolley on different surfaces to see how $Fᵧ$ affects normal force and friction.

• Up a slope: Place the track on a small incline to see if vertical thrust helps or hinders motion.

• Reverse thrust: Point the fan backwards and explore deceleration and braking force.

• Variable mass: Add different masses to see the effect on acceleration for the same fan angle.

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📚 Learning Outcomes

• Understand how vector components of force affect motion.

• Apply Newton’s Second Law to non-standard force directions.

• Use experimental data to confirm theoretical predictions.

• Practise data logging, plotting graphs, and interpreting results.

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🧠 Conclusion

This experiment takes a simple idea — a fan and a trolley — and turns it into a rich, hands-on investigation of force vectors, acceleration, and Newton’s laws. It’s an ideal activity for secondary school physics classes, science clubs, or even independent investigation projects.

The ability to visualise and measure the change in acceleration due to a changing angle of thrust makes this one of those rare experiments that is as visually striking as it is educational.