Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solids and Fluids

  1. Nov 20, 2003 #1
    Some of the problems, I really don't know how to even set up the problem. I don't want an answer for them, but I need an idea where to start.

    1. Gauge pressure in both tires = 690 kPa.
    Bike and the riders mass = 90.0 kg.
    Find area of contact of each tire with the ground if each tire supports half the total weight.
    I read the section that this problem corresponse to and could not figure out where to start.

    3. Boat overloaded such that water level is 1.0cm below top of boat.
    Total lenght= 4.5m
    height= .3m
    width= 2.0m

    Find combinded mass of people and boat.

    I'm not sure how to to this one.
    I drew a FBD and got...
    Force of boat=mg
    Density of water x volume of object x gravity= mg
    ?=2610 kg

    4. Irregularly shaped piece of metal
    weight=.882 N. When submerged in water irregual object is suspended from scale rading .735 N.
    Find volume and density of object.
  2. jcsd
  3. Nov 21, 2003 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Think Pressure = Force/Area; the force must be enough to support the bike + rider.

    Assuming the boat is rectangular, you got it.

    The scale reading is the force that the scale must pull up to support the object. So, consider the forces acting on the object when it's submerged: The scale is pulling up, the bouyant force (water) is pushing up, and the weight is pulling down. These forces must balance.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook