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physica

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Everything posted by physica

  1. Thank you for the reply. A is find the spring force (i used hooke's law) and B is find the damper and any other forces acting. I only got 3 forces: the weight of the mass, the spring and the damper. When using Newton's second law I can some up with a differential equation similar to the one stated in D but I have a -mg and I don't know where the my^.. came from. I've looked at many examples and they always give a negative mg if the unit vector is pointing upwards. Y is a resultant force of an earthquake but I thought this this would be sinusoidal with a sin or cos function. The -mg and the inserted my are the two parts that completely baffle me. C is also mildly confusing. I get the displacement vector for the mass from the origin to be: d+y-x, I understand that differentiating this with respect to time twice would get the acceleration but what would this denote?.... is this where the my and negative mg come from?
  2. I feel like a complete idiot. I’ve spent hours on this low mark question but I just don’t get it. I’ve got the 3 forces: W=-mg, H=-k(x-L0)i, R=-rx but I am clueless about C and D let alone how to tackle them. What are they even asking? I’d email my lecturer but he never replies.
  3. many thanks for this. Now kicking myself but the problem is now solved. thank you so much.
  4. There has been experimental evidence linking knowledge to arrogance. The Dunning-Kruger effect (winning a Nobel prize in 2000) makes the observation that the more a typical person knows the less confident they are in their abilities. On a personal level I can relate to this. After university I spent 3 years working in the emergency room. I was so confident I believed the propaganda the hospital told me and I thought there was nothing I couldn’t understand. I thought I understood science and still manage to pull 12 hour shifts seeing patients. After three years I got bored and went back to university. I am now in my second year of my physics degree and I can tell you it has knocked me into shape. The mathematics behind probability has shown me how illogical I was. I am passing but I can tell you it is by no means find it easy. I would happily put my hand up and say I was arrogant back then. However, we have to be careful who we brand arrogant. I have seen multiple abuses of the word. People are of the habit of using it as a cheap defence when they simply don’t like hearing what the person is saying. My mind goes back to a surgeon who I used to work with every now and again. She would comment strongly on absolutely anything even when it was clear she knew nothing about the subject she was commenting on. Needless to say she wasn’t liked at all but no one put her in her place because she had mastered this trick of labelling someone as arrogant the moment they disagreed with her. Another example is Richard Dawkings. People love to call him arrogant but all I have seen is him say he doesn’t believe in something that doesn’t have scientific proof. He doesn’t claim to know anything above what science tells us, and he doesn’t claim to know more than the people he debates with. I have never heard him claim some great ability. If someone has a different opinion on Richard I would love to hear it as I have only seen him from my point of view.
  5. I understand the concept of potential energy and I am aware that this question may not seem too complex. I have an issue of approaching the question. I do not want any answers, I just need some help as I am completely clueless on how to go about solving it. I am slightly confused as to what it's actually asking. I have emailed my tutor a number of times and he hasn't replied.
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