Recent content by RateOfReturn

  1. R

    Problem about a block of ice melting (specific latent heat)

    Energy lost by water = Energy gained by ice Energy lost by water = 0.16 x 4200 x (100-t) Energy gained by ice = 0.205 x L + 0.205 x (t) (where t is the temperature at thermal equilibrium). However, there does not appear to be enough info to continue. The solution, however, considered t to be...
  2. R

    Relationship between diameter and elastic potential energy of a wire

    Is the force in the formula Stress= Force/area and the force in Force= spring constant times extension, the same force ?
  3. R

    Relationship between diameter and elastic potential energy of a wire

    I am not familiar with how k and cross-sectional area are related. Although, I'm thinking if the cross-sectional area quadruples, then the force needed per unit extension must also quadruple. So k must quadruple ?
  4. R

    Relationship between diameter and elastic potential energy of a wire

    Sorry, it was a typo- I meant to say stress = force/area. I'll edit the original question.
  5. R

    Relationship between diameter and elastic potential energy of a wire

    I think the answer is that the elastic potential energy will be a 1/16th of the original value. This is my reasoning: 1) If the diameter doubles, the cross sectional area is 4 times the original value. (from A= πr2). 2) F= stress/area. Force (load is the same). If cross sectional area...
  6. R

    Centre of Mass/Tipping Point Question

    Thank you, after re-calculating I get 2.256..., which is consistent with the answer to 2.s.f. It unfortunately appears to be a printing error.
  7. R

    Centre of Mass/Tipping Point Question

    I drew out a small diagram to illustrate my attempt. I interpreted 280 degrees from the vertical as 10 degrees from the horizontal. Using trig I solved for the h, which I get an obviously incorrect answer. The actual answer in the book is 2.3m,
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