Velocity Of Atrolley Investigation

Title: An Investigation into how different Factors affect the stopping distance.

Input variable: Surfaces

Output variable: Weights

Aim: To investigate what different factors affect the stop distance of a vehicle?

Hypothesis: I predict that the thicker, rougher the surface the more friction there will be. The smoother the surface the less friction there will be. I also think that the more mass there is the further the vehicle will go.

Intro/ Planning:

I am planning to carry out a practical experiment in which a trolley will roll down a ramp at a height of 15 cm. the time from when it leaves the ram will be calculated as its stopping distance. I will use different surface to test how friction will vary and affect the stopping distance. I will also add weights to the trolley to see how the mass of the object will affect the stopping distance of the trolley. The reason for my prediction that the greater the mass of the trolley the further the distance is because the more mass there is the greater the potential energy the trolley has at the top of the ramp. When the trolley rolls down the ramp the kinetic energy starts to build up. The original potential energy is converted to heat energy. The diagram and equations below illustrates how the mass of the object affects the stopping distance.

When the trolley is about to start it's descent it has its maximum P.E. when it has reached the ground and is flat on the surface all the P.E has been converted mostly into Kinetic Energy all though accurately some of the energy has also been converted into heat and sound energy.

Potential Energy = Mass x Gravity x Height

Kinetic Energy= Mass x 0.5 x m/s2

As you can see from the above equations the more mass there is the further the trolley will travel. My prediction is theoretically right according to the two equations above as the greater the mass the more momentum there will be and therefore the further the trolley will travel.

The second half of my prediction is that the smoother the surface the further the trolley will go. The reason for this is linked to my first half. As the trolley reaches the floor it will have transferred P.E to K.E. If the surface is rough then all the energy will be turned into heat and sound energy much faster than on a smooth surface. Therefore on a rough surface like a thick carpet the trolley will come to a halt much faster than on a smooth surface.

In my real practical I am going to use data logging to work out the stopping distance. I will use this because it extends my investigation and is the most reliable way to carry out my investigation. I have already carried out a preliminary practical to the investigation. I am going to use the data logging on the anomalies to get a precise result. During my preliminary I got fairly accurate results but to broaden my investigation I am going to use data logging and two different surfaces in my real practical to prove my hypothesis. I will note down the Stopping time and the stopping distance to see a correlation into how the surface and weight affects the stopping distance and time.

I have obtained evidence from internet and science books that the heavily loaded vehicle will take longer to stop (greater mass). An example of this is a car and a caravan. The car will have a shorted braking distance than the caravan. Also the grip of your vehicle will affect the stopping distance. This means the more friction there is the faster a vehicle will stop, also whether the surface is smooth or rough. A good example of this is a car going on Ice and in long grass the car will skid in the ice but will slow down instantly in the long grass.

I am first going to show what I did for my preliminary work.

Preliminary Equipment

1x trolley

1x Ramp

4x weights (100g each)

1x Surfaces

1x Wooden Plank 15cm

1x Stop Watch

2x 1metre rulers

Preliminary Method

1. Collect apparatus and set up as shown in the diagram. (above)

2. Weigh the trolley and note it down on your results table

3. Set timer to 0.

4. Use the Table top surface first

5. Release the trolley from the highest point on the ramp as shown in the diagram.

6. Simultaneously as the trolley reaches the surface start the timers. This is the time taken to brake. At this point all the P.E has been converted to K.E.

7. When the trolley stop press stop on the timer and note down the 'stopping time'.

8. Also note down the distance by measuring the distance between the back of the trolley and the bottom of the ramp.

9. Each time add a 100g weight to the trolley. This is to investigate how weight effects the stopping distance

10. Do this 4 more times. Each time add an extra weight so at the end you end up with 4 weights on the trolley

11. Note down results accurately and draw graph.

Preliminary Results

Preliminary Evaluation/Conclusion

From my preliminary findings I have discovered that my prediction has been practically proved. Although I did find an anomaly in my preliminary as I have circled above. The reason for the anomaly is that we did not have the most precise equipment and the investigation