Recent content by 7starmantis

  1. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    So basically since\rhogv = 2N Volume = 2N / \rhog Volume = 2.0X10^-4 Then the weight in air is 15N / 9.8 = 1.53kg \rho object = m/v = 1.53kg/2.0X10^-4 = 7650 That make sense? I hope so, cause it does to me... :)
  2. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    We did a lab like this, but my teacher hasn't returned our lab reports yet and it has all my data in it. I just can't for the life of me understand how to setup the problem.
  3. 7

    Truck weight from ferry sinkage of 0.0367 m

    Thats ok, I just wanted to understand the concept and make sure I was setting it up right.(although it does sound like a big weight) Thank you very much for your help, you explained it in a way I could understand. I really appreciate it! a lot!
  4. 7

    Truck weight from ferry sinkage of 0.0367 m

    Ok, so Vol of water displaced is: vol = a*h = (15.24X6.10)*(.0367) = 3.41m^3 Then: m = v*\rho = (3.41)*(1000) = 3410kg Wt = 3410kg * 9.8 = 33418N So that is the weight of the water displaced which is also the weight of the truck. That makes sense to me. Why couldn't I figure that out...
  5. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    I'm so frustrated by this problem I can't even think straight anymore. I don't understand what you mean by it being an additive term, isn't it multiplied in the equation? But at this point I can't even figure out how to solve the equation with or without it.
  6. 7

    Truck weight from ferry sinkage of 0.0367 m

    Could I not find the pressure at that depth by \rhogh (1000)(9.8)(.0367) = 359.7pa F = PA = (359.7)(15.24m X 6.10m) = 33439.2 / 9.8 = 3412.16 kg ?
  7. 7

    Truck weight from ferry sinkage of 0.0367 m

    This is making me feel really stupid. I understand the concept that the water displaced will equal the weight of the truck, but I can't seem to find an equation to find that mass of the water. I can't determine the volume or weight of the ferry.
  8. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    I didn't get that he said to set them equal to each other, but I also don't know the density of the air. So: m*g - volume of the object* density of the air* g = m*g - volume of the object* density of water*g I have everything except density of air.
  9. 7

    Truck weight from ferry sinkage of 0.0367 m

    So we are looking at something like: Buoyant Force only changes once the truck drives onto the ferry. So the displaced water equals the weight of the truck? That would mean... Buoyant force (wt of truck) = P2A - P1A P1 - ATM pressure P2 = \rhogh A = length X width so... =...
  10. 7

    What is the Correct Radius of a Brass Rod Given Its Mass and Density?

    Ah, then I just questioned myself for no reason. I already had the correct answer. Correct?
  11. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    I'm confused, that still leaves me with two separate values for mass. Which value would I use in the density equation?
  12. 7

    What is the Correct Radius of a Brass Rod Given Its Mass and Density?

    Yeah I forgot to complete the area units, sorry. I didn't think area = volume / length was the right equation. If it is then I have the right answer already, right?
  13. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    How do I go about finding the density? Don't I need to find volume first then use volume in the density equation?
  14. 7

    What is the Correct Radius of a Brass Rod Given Its Mass and Density?

    [SOLVED] Radius Problem A brass rod (density = 8470 kg/m3) is 12cm long and weighs 20N. What is the radius of the rod? I'm confused when finding area. I don't think I'm using the right variables. volume = mass/density v = 2.04 kg / 8470 kg/m3 = 2.4X10^-4 Area = volume/length? A = 2.4X10^-4 /...
  15. 7

    Object weighs 15N in air and 13N in water, which mass to use for density

    An object weighs 15N in air and 13N when submerged in water. determine the density of the object. Am I setting this up correctly, I'm confused about the two masses. Volume = W(air) - W(water) / pg 15-13 / (1000)(9.8) = 2.0x10^4 p(density) = m/V What mass do I use here though, the one in air or...