# Speed Of trolley

Science Physics coursework

What Affects the Speed of a Trolley Running on a Runway?

Introduction

In this investigation I plan to find out what affects the speed of a trolley rolling over a runway. The speed can be affected in various ways. Below is a list of variables:

1. Steepness of the runway.
2. Surface of the runway.
3. Shape of the trolley (whether it is aero-dynamical or not).
4. Force exerted on the trolley.

One of these variables above will be used in the experiment in order to see how the speed is affected (Dependant variable). All these variables can affect the speed of the trolley by either speeding or slowing it down. For example: for variable 2, if the surface is rough, friction will slow it down, if the surface is bumpy then the trolley will either slow down or stop. Variable 4, if you exert a bit of force then the trolley will go faster. If you push the trolley it will go faster than not pushing it. In this investigation the Dependant variable is the ‘Steepness of the runway’.

Aim

The aim is to find out what affects the speed of the trolley running on a runway.

Variables

Variable 1: Steepness of the runway – trolley going downhill

Prediction: When the slope/steepness of the runway is higher the speed of the trolley will be faster.

Potential energy is the reason for the increase of velocity.

When the slope is steeper, the height of the runway increases. When the height increases the potential energy of the trolley also increases. All the potential energy is converted into kinetic energy during the motion of the trolley. At the bottom there is no potential energy so potential energy equals to 0. At the top potential energy is used not kinetic energy, so there is no kinetic energy. This means at the top kinetic energy is equal to 0.

So generally at the top (when the trolley is at the top of the runway) there is potential energy and at the bottom (where the trolley is at the bottom of the runway) kinetic energy has been used.

Variable 2: Surface of the Runway

Prediction: If the surface of the runway is smooth then the trolley will travel faster. If the surface of the runway is rough then the trolley will travel slower due to friction between them.

The trolley will travel slower if the surface of the runway is rough. This is because friction is higher in rough surfaces than it is in smooth surfaces. Frictional force is working against the flow of motion. So the trolley goes down the runway but friction is trying to slow it down so the force becomes negative. One of Newton’s law (the law of ...