GCSE Physics Coursework, Spinners, Forces and Motion

Physics coursework; Spinners

Introduction

My investigation is about how the number of paperclips added onto a paper spinner affects the time taken for the spinner to fall from a height of 3m. I predict that the time taken for the spinners to fall to the ground will decrease when the number of paperclips added increases. This is because heavier objects fall to the ground faster than objects that are lighter. The force of gravity is directly proportional to the mass of the object. The equation to measure the force of gravity is :

Fg = M x Ag

Force due to gravity = mass x acceleration due to gravity (-9.8m/s)

Forces

To find out what is going to happen to the spinner when it is dropped from a height you have to look at what forces are acting on the spinner. There is always one force that acts on everything on earth and the force id called gravity. Gravity is a downward force that attracts everything on earth to its centre or core. The force of the gravitational pull is equivalent to the weight of the object. Theoretically the higher the weight the greater the force of gravity, so the spinner should fall to the ground quicker with more paperclips on it.

There is also another force called air resistance that pushes up on the spinner and when it falls. Objects with a large surface area have a greater force of air resistance so the time they take to fall will be more.

Spinner

A spinner is a bit like a helicopter but the blades are quite different. On a helicopter the rotor blades are curved at the top and flat at the bottom, this causes air to flow faster over the top so there is more pressure underneath the blades. This high pressure underneath the blades allows the helicopter to take off. A spinner has wings that are flat top and bottom, so there is equal pressure, so it does not take off, but due to air resistance the flat surface of the spinner has an upward force slowing it down.

Preliminary Method

My initial Idea was to make a spinner and drop it from a length of 2 metres; this would require two 1metre rulers. Firstly I got a piece of A5 card (card any bigger would have a wings span too large and a piece of card any smaller will have a wing span too small) and drew out the shape of the spinner with a pencil and ruler, this was important so that I knew what bits I had to cut out and how my spinner would look. Then I cut it out with a pair of scissors and folded the card to make it a spinner and attached a paperclip that weighed 0.43 grams. The paperclip was weighed using a weighing scale that read correct to two decimal places, and pressed the ‘tare’ button to make the weight zero before weighing the paperclip to show the true weight of the paperclip. Then I aligned the two rulers’ one on top of the other (there were not any 2m rulers) and dropped the spinner from the top of the ruler. At a count of 3 the spinner was let go, the stopwatch (was useful to measure the time it took for the spinner to dropped to the ground) would be started and as soon as it hit the ground the stopwatch was stopped. I did three trials for each experiment to ensure reliability and after every time the three trials were over I would take away one paperclip so the weight would decrease.