Recent content by MaryBarnes

  1. M

    A container holds 8.0kg of water at 25degC...

    i attempted the answer: Q total=mcwΔt+msLf =8.0kg*4200j/kg*(100°C-25°C)+2.0kg*2.3*106 =7.12*106J
  2. M

    Check my answer for power output question

    its 20, but my answer has a negative. i was going to edit it but don't know how to
  3. M

    Check my answer for power output question

    =0.25kg*2100J/(kg °c)*((-10°C) - (-30) °C) =525*20°C =10500J P=10500J/150s =70w is this ok?
  4. M

    Check my answer for power output question

    im going to retry my answer. will post shortly
  5. M

    Check my answer for power output question

    3.3*105 is the latent heat of fusion for water that ive been given, now i see where i may have messed up.
  6. M

    Check my answer for power output question

    Homework Statement a 0.25 kg piece of ice at -30°C is warmed by an electric heater and the following graph of temperature is produced. -use the information on the graph to determine the power output of the heater the graph shows that the ice went from -30degC to -10 degC in 150s Homework...
  7. M

    A container holds 8.0kg of water at 25degC...

    Homework Statement how much energy must be added to the water to create 2.0 kg of steam? Homework Equations The Attempt at a Solution I have no idea how im supposed to figure the answer out. what formulas do I use?
  8. M

    Calculate the Net Force

    Ok, thanks for mentioning that. Thank you for all of your help! Now I actually understand how work with these equations!
  9. M

    Calculate the Net Force

    I tried the third answer using the sin and cosine law. Is this right? fnet^2=2N^2+17N^2 -2(2N)(17N)cos45 Fnet=square root of:244.9 Fnet=15.6N or 16N sin45/15.6N=sin/2N sin=2Nsin45/15.6N sin-1(0.0906) =5.2deg 45deg-5.2deg=40
  10. M

    Calculate the Net Force

    if i subtract 24deg from 24 deg i get 0? is this really the answer? for the third question i'm just going to break it down into components because that way makes way more sense to me. maybe that's not the expectation, but i don't think id loose any marks for doing so. Thank you for all your...
  11. M

    Calculate the Net Force

    so now I've tried tried what you suggested and I got 24.48 deg. Is this right?
  12. M

    Calculate the Net Force

    "In your third answer, the magnitude of the net force ##F_{net}=24N## is correct, but the angle is incorrect because you have used the Sine Rule in some triangle that doesn't exist. I suggest you to draw a sketch for each problem with a completed parallelogram and angles properly annotated so...
Top