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tdls1234321
Dec 23, 2009, 04:31 AM
Sau-Lan has a mass of 47 kg. She rides the up escalator at Ocean Park in Hong Kong. This is the world's longest escalator, with a length of 227 m and an average inclination of 31°. How much work does the escalator do on Sau-Lan?

Clough
Dec 23, 2009, 04:38 AM
Hi, tdls1234321!

Are you looking for a direct answer to the question, or for someone to come along to advise you for how you might come up with the correct answer yourself, please?

Thanks!

tdls1234321
Dec 23, 2009, 04:40 AM
Advice would be appreciated! Thank you :)

Clough
Dec 23, 2009, 04:47 AM
Hi again, tdls1234321!

Thank your for letting me know that! Now, the best people to help you to understand how to answer the question might not be online here or might even be asleep.

So, it's a matter waiting for the best person to come along who can address your question. That can take some time and patience...

Too many times, we have students coming on here just looking for direct answers. That's not the way that this site works.

I'm glad that you're looking for how to solve the question rather than just looking for the answers.

Thanks!

Unknown008
Dec 23, 2009, 07:57 AM
What is work?

It is moving an object and is given by the product of the force acting on it, and the displacement in the direction of that force.

It's asking you what is the work done by the escalator.

Well, it's applying a force on Sau Lan and she is moving upwards, along the inclination.

What you need to know is:
1. The force acting on Sau Lan
2. The displacement Sau Lan experiences, which is in the direction of the force acting on Sau Lan.

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Another way of looking at it:
The work here also refers to the energy that the escalator used. Applying the law of conservation of energy, the energy used by the escalator is gained by Sau Lan.

Sau Lan gains only gravitational potential energy when she is on the escalator. How can you find that energy? (Using the formula E=mgh)

~~~~~

Either way, you get the same answer. I leave it to you to do the job now. :)

mathwiz3502
Dec 23, 2009, 09:57 AM
Although it is a simple machine I believe that you should find the height of the escalator, you already have a hypotenuse, right angle and another angle (31). And with two angles you know the other is 59

So the height would be the shortest "side" and is in between 90 and 59.

Does this help?