# Stoppping Distance

Topics: Force, Friction, Classical mechanics Pages: 7 (2454 words) Published: March 6, 2013
Title: Stopping Distance
Aim: To investigate
1. The effect different surfaces have on the stopping distance of a trolley. 2. The effect different masses have on the stopping distance of a trolley. Hypothesis:
1. The rougher the surface, the shorter the stopping distance. 2. The larger the mass the further the stopping distance. Introduction:
The purpose of this research was to investigate how different surfaces as well as different mass effect the stopping distance of a physics trolley after rolled down a ramp. The aim is to test the hypothesis that the rougher the surface, the shorter the stopping distance and the larger the mass the further the stopping distance. Friction is the force which opposes the motion of one surface over another, and is the means through which a vehicle may move in a straight line, or may turn or stop. Stopping distances are affected by friction, the more friction the shorter the stopping distance, the lower the friction the further the stopping distance. A mass of an object is the fundamental measure of the amount of matter in the object. Weight is the force of the gravity on the object whereas mass is the weight of the object without gravitational pull. Momentum is mass in motion, momentum refers to the quantity of motion an object has. How much momentum an object has depends on two variables, the mass and the speed. Speed is the distance a moving object covers in a certain time. An object that covers long distance in a short period of time has a high speed whereas another object that covers the same distance in a longer period of time has a lower speed. In terms of an equation, momentum is equal to mass multiplied by its speed, therefore an object with a large mass or speed has high momentum. An object with high momentum is a lot harder to stop compared to an object with a lower momentum. This is because with more momentum, more force is applied towards the direction of which the object is moving, therefore the object is pushing harder against the force of the friction hence the friction between the two surfaces is not as effective.

Materials and Methods:
1. Surface
A two metre long ramp was inclined 11.5cm above the grass surface. A physics trolley was let go from the top of the ramp, than the distance from the bottom of the ramp to where the physics trolley had stopped was measured with a measuring tape. This method was repeated five times, nothing was altered or moved and the same ramp and physics trolley was used, as well as the person who had let go of the trolley, from the top of the ramp in the first experiment. The method was repeated 5 times and the data was recorded in order to find an average, to get the most accurate result possible. This identical method was repeated on three other different surfaces, concrete, lino and pavers, all five times each, making sure that no other variables were altered. 2. Mass

Surfaces
Surfaces
The above method was repeated once again with the different surfaces. But this time 100g weight was taped onto the physics trolley and let go from the top of the ramp. The distance was collected from the bottom of the ramp to where the trolley had stopped. This exact method was repeated again five times, than the measurements from the experiments were averaged. Next the same procedure was again repeated with the different surface areas but with a weight of 200g. Measurements were collected and averaged. Than the weights increased to 300g than at last 400g, all at while it was made sure that no other variables were altered but surface and mass. Results

Experiment 1.
Stopping Distance Variable 1- Surface|
Surface| 1| 2| 3| 4| 5| Average|
Grass| 88| 82| 88| 91| 83| 86.4cm|
Concrete| 236| 280| 243| 278| 288| 265.0cm|
Lino| 270| 291| 287| 294| 292| 286.8cm|
Pavers| 197| 188| 187| 170| 182| 184.8cm|

Experiment 2.
Stopping Distance Variable 2- Weight-100g|
Surface| 1| 2| 3|...

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