# Investigating the Breaking Distance of a Cart

## Investigating the Breaking Distance of a Cart

Physics SL

1. INTRODUCTION

Braking distance is the distance travelled by an object when the brakes are applied. In this experiment we are looking at the stopping distance of a crate which is similar ot the concept of braking distance covered by a moving object.

1.2 Research Question

The purpose of this experiment was to investigate the factors affecting breaking distance of a moving object, which in this case was a metal cart. Within this experiment it was established that there is a relationship between the initial velocity of the cart and its breaking distance.

Why it was decided to take into account the initial velocity was because of the simple dependency, which was evident after calculations. Since during braking of an object the kinetic energy (EK) becomes heat energy. Thus the following equation can be written down

½ mv20= Fd

In order to come to distinct results a linear graph should be obtained. Thus we should have an equation, which is simple and shows a distinct dependency. We can simplify the equation to show that distance is directly proportional to the square of the speed.

dv20

1.3 Hypothesis

Thus the hypothesis for this experiment is that the initial velocity of the crate will have an impact on the braking distance of the moving crate.

2. MATERIAL & METHOD

2.1 Apparatus

Light gate

Meter ruler

Track

Metal crate

Two rubber bands

2.2 Method

A track was set up underneath the single light gate. To calculate the initial velocity a photocell was used. Using one light gate which was set to the mode of calculating collision the initial velocity was possible to come up with.  With the ruler placed besides the track in order to see the distance traveled by metal crate. An attached piece of cardboard to the crate was used in order to receive the tame taken for the crate to pass through the light gate. To find out the initial velocity the width of the cardboard flag was divided by the time taken for the crate to pass the light gate.

v0 = ∆d / ∆t

The releasing of the crate was one difficulty encountered whilst conducting this experiment. Each round the crate was released to motion with the help of rubber bands. By attaching two rubber bands to the end of the track the releaser for the crate was set up.  Pulling the crate with varying extensions with the band would result in differing initial velocities. No specific way was ensured to give out specific forces on the crate. The only way was to repeatedly release the crate with varying extensions of the elastic band. Thus it was problematic to ...