Recent content by Henrybar

  1. H

    Why doesn't Q=0 instead of Q=W if T=constant in first law?

    Q=W+ΔU Heat added to system=work done by system + change in internal energy of system
  2. H

    Why doesn't Q=0 instead of Q=W if T=constant in first law?

    I should have mentioned my question does particularly concern the isothermal expansion of gas. I have a few things I would like final clarification on. How is an isothermal expansion of a gas maintained if there is a temperature imbalance (and heat transfer)? Is it because the experimenter is...
  3. H

    Why doesn't Q=0 instead of Q=W if T=constant in first law?

    Q=W-ΔU Heat added to system=work done by system - change in internal energy of system
  4. H

    Why doesn't Q=0 instead of Q=W if T=constant in first law?

    My understanding of heat is the energy transferred as a result of temperature imbalance between systems. If two systems at different temperatures are in contact with each other, a temperature change for both systems and an energy transfer Q is occurring. It is known that Q=W for a closed...
  5. H

    How does the law of conservation apply under these condition

    Can you not read what I wrote beneath that part?
  6. H

    How does the law of conservation apply under these condition

    A person of 60 kg is holding on a rope of 3m while standing on a the ledge of a building of height 7m. The rope is fixed to a point at roughly eye level 3 m from ledge. The person walks off the building and is swung in a vertical circle. If the person let's go at approximately the same height he...
  7. H

    Will speed increase under these conditions?

    A mass is tied to a rope, that rope is attatched to a pole coming out of the screen. The pole is being moved by a person to cause the mass to rotate in a verticle circle at constant speed. A second pole coming out of the screen is introduced within the radius. The second pole interacts with the...
  8. H

    How do I estimate how tall this building is?

    How do I estimate the height of the tall building spiderman swings to at 0:48? I need it for a physics assignment. What does you're intuition tell you? (I've never lived in a city full of buildings). Is there a way to estimate it using physics? I'm not sure that building actually exists.
  9. H

    Where does g force fit in this centripetal motion question?

    a car goes around a vertical circle; determine the period of one cycle if the radius= 6m mass=800kg, gravity=9.8m/s^2 gforce = 6g my attempt at the bottom of circle: fnet=ma fn+fg=(mv^2)/r fn+fg=(4∏^2mr)/t^2 t=√4∏^2mr/fn+fg t=√4∏^2(800)(6)/(fg+fg) <-----value of fn and fg will be in opposite...
  10. H

    Calculating Mass in Box 3 of a Pulley System

    Question Summarized: The box in the middle is remains motionless; how much mass was placed in box 3? box 1: 35kg middle box: 95 kg box 3: ? kg Attempt at the problem:
  11. H

    Air resistance, changing position in free fall?

    "Fan" as in a manual fan, not a fan that rotates and blows air.
  12. H

    If an object rolls off a tabletop is the vertical velocity initially 0?

    Please explain!
  13. H

    Air resistance, changing position in free fall?

    Let's say that I have a stick with weight evenly distributed throughout. I attach a fan to one end of the stick, then balance it from its new centre of mass. I measure the distance from the ground to the stick then drop it. The stick tilts up towards the side generating more air resistance (fan...
  14. H

    Determine acceleration of gravity through experiment?

    olivermsun - the purpose is to demonstrate that 9.8 m/s^2 is in fact the acceleration due to gravity. As long as the experiment achieves a number close to 9.8 and is repeatable, then it is fine.
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