4 Energy – Part C “Work Energy and Power”

Syllabus Aims…

4.11 know and use the relationship between work, force and distance moved in the direction of the force:

work done = force × distance moved

W = F × d

4.12 know that work done is equal to energy transferred.

4.13 know and use the relationship:

gravitational potential energy = mass × g × height

GPE = m × g × h

4.14 know and use the relationship:

kinetic energy = ½ × mass × speed²

KE = ½ × m × v²

4.15 understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work

4.16 describe power as the rate of transfer of energy or the rate of doing work

4.17 use the relationship between power, work done (energy transferred) and time taken:

power = work done / time taken

P = W / t

Resources…

Use this PowerPoint for lesson resources…. 4C Energy Work and Power
LED bulbs

Useful Videos…

Episode 8 Work

Amazing Eureka Physics video series from 1 to 30 which through cartoon go through the amazing world of KS3 to A-Level Physics teaching with key concepts.

First released in Canada but ...still going strong![+] Show More

Episode 8 Work

Amazing Eureka Physics video series from 1 to 30 which through cartoon go ...

Episode 9 Kinetic Energy

Amazing Eureka Physics video series from 1 to 30 which through cartoon go ...

Episode 10 Potential Energy

Amazing Eureka Physics video series from 1 to 30 which through cartoon go ...

The Physics of Starship Battles: Lasers and Kinetic Energy UPGRADED SpreadingtheMuse Productions

By Bernard Finnigan. An explanation of the formula for kinetic energy and ...

GCSE Physics - Energy Stores, Transferring Energy & Work Done #1

In this video you'll learn: - The 'conservation of energy principle' - The ...

Led replacement bulbs

These are cool new led bulbs which are energy efficient. Advantages of LED ...

These are cool new led bulbs which are energy efficient.

Advantages of LED Bulbs

The operational life of a LED lamp (up to 50,000 hours) is in contrast to the average life ...of an incandescent bulb, which is approximately 1000-2000 hours. For lights in very inaccessible places, using LEDs would eliminate the need for difficult bulb replacement for many years. It really is simply a case of fit-and-forget!

The cost of LED lights compared to traditional incandescent bulbs

The main advantage of LED lighting is clearly in the energy savings (and therefore money savings!) which are achieved. The way in which LEDs achieve this energy saving is by the amount of heat they create. Traditional incandescent bulbs lose up to 90% of their power on creating heat which is wasted. LEDs save on power consumption by generating considerably less wasteful heat.

The cost savings are considerably higher than just the energy saving if you consider the cost of 30-50 replacement incandescent bulbs. With LEDs, there would be no replacement bulbs required for many years and they often pay for themselves in energy savings in less than a year of use.

For commercial premises like retail outlets, hotels and offices, there is a significant maintenance cost in replacing light bulbs which can be virtually eliminated. This is an important point, especially where there are a large number of bulbs in place. Eliminating the constant need to replace bulbs by changing to LED options can be very attractive, and after the cost of replacing halogen bulbs is taken into account, LED bulbs really are the ultimate energy saving bulb.

Compact Size

As the LEDs which provide the light in the bulbs are so small, the high powered LED bulbs are direct replacements for halogen bulbs in terms of size. This gives LEDs a distinct advantage over energy saving CFL bulbs which are generally larger than their halogen counterparts, and can look unsightly in some elegant light fittings.

When it comes to display or accent lighting, the compact size of LED light bulbs, as well as the availability of coloured lighting provides for very versatile lighting which is appropriate everywhere from retail displays to Christmas lights in homes.

Practical Advantages

LED light bulbs represent the safest form of lighting and even when they go wrong, they are still not dangerous to be around, unlike incandescent bulbs which generate lots of heat when in use and have even been known to explode when things go wrong. LEDs are not strictly light bulbs, they are an electrical circuit (semiconductor). They do not contain filaments and therefore are not prone to the usual light bulb problems associated with incandescent bulbs.

LEDs will invariably last 30 to 50 times longer than standard incandescent bulbs, whilst using an average of 90% less power which makes them ideal for places where lights are switched on for lengthy periods of time. More durable with no fragile parts, the bulbs generate virtually no heat and are therefore safe in almost all areas around the home. The cool running temperature of LEDs could reduce air conditioning costs, and the fire risk associated with overheating incandescent bulbs is not an issue with LEDs.

As LEDs are very strong and durable, they are able to endure vibration so they are appropriate for use in many places where existing bulbs are subject to regular failure, eg around heavy machinery. They are also able to tolerate low temperatures and therefore allow more flexibility in their use.

LEDs do not produce any UV (ultraviolet) or IR (infra red) radiation, and can thus be used to light paintings or other precious artefacts without causing any fading. Unlike CFL or fluorescent lighting, LED lighting also does not flicker, and this reduces eye strain and other problems associated with flickering lighting solutions.

Taking Care of the Environment

Taking care of the environment has become a way of life in the 21st century, and we all have a duty to try and reduce our carbon footprints, be it at home or in our businesses. An easy way to make a start in improving the efficiency of our homes and businesses is through LED lighting. Environmental specialists list improving energy efficiency as an important factor to reduce our impact on the environment. LED lights use up to 90% less electricity than standard halogen bulbs and have an extremely long lifespan which equates to considerably reduced carbon emissions and less waste because fewer lamps need to be disposed of.

Have you seen the light yet?[+] Show More