Doresoom
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 Aug 29 awarded Informed Aug 11 comment At what speed (km/h) are the ride-goers (harnessed at opposite ends of ends of “propeller”) travelling? ...it says 100 kph in the text Apr 4 comment Ice cube on a scale @MircBreitschuh, are you confusing change in density with change in mass? Apr 4 comment Ice cube on a scale I'm totally going to start referring to water as molten ice now. Apr 4 awarded Editor Apr 4 awarded Citizen Patrol Mar 21 comment Effect of water pressure on sinking objects It should be m*g-rho*g*V-Fdrag. rho will change with water temperature, so the buoyant force should increase as the depth increases. Mar 21 comment Effect of water pressure on sinking objects I don't think your Fh is correct. The net hydrostatic force should be approximately zero, since you have pressure on the surface area on the bottom pushing upward as well. In fact, it should be very slightly upward for tall objects, since the pressure at the bottom of the object will be slightly higher than the pressure at the top. Sep 4 awarded Commentator Sep 4 comment What will happen if a plane trys to take off whilst on a treadmill? The "difference in air speed below and above the wing" does not provide the lift. Airplanes gain lift by deflecting air downward. allstar.fiu.edu/aero/airflylvl3.htm Nov 28 comment Solving an indeterminate triangle truss structure (statics) The first setup drawn is not statically indeterminate. If you had a truss member vertically from A to B, then it would be. The second setup drawn is not actually constrained and will collapse at the slightest imbalance. Use the joint method and consider the point at which the force is applied. You know the forces in the two members are in the direction of the members. You've got two equations (x and y) and two unknowns - the magnitudes. Nov 16 awarded Critic Nov 14 comment Is it possible to calculate weight of person with sensors found in today's smartphone? There are a few problems with your train of thought. Objects accelerate due to gravity at the same rate, no matter their mass. True, there will be small differences due to air resistance on the person's cross-sectional area, and F=GMm/r^2 does vary minutely by the mass of the person, but not anywhere on the magnitude that can be picked up by a MEMs accel. Another issue is that accels don't measure velocity - they measure acceleration. Nov 9 comment Force on rope with accelerating mass on pulley Think of it this way: If you stand next to a table and push downward on the table with your hands, the floor under your feet will be holding up your weight minus the weight you place on the table. So the tension on the rope (seat side) is holding up the kid's weight minus the weight he places on the other side of the rope. Nov 8 comment Force on rope with accelerating mass on pulley You still need to add F acting upward on the kid, since he's exerting F down on the other end of the rope. Nov 8 awarded Teacher Nov 7 comment Why do rockets have multiple stages? This was my first thought as well when reading the question. Nov 7 comment Force on rope with accelerating mass on pulley I went ahead and gave a full solution to this since you had already posted the correct answer yourself. Nov 7 answered Force on rope with accelerating mass on pulley Nov 7 comment Force on rope with accelerating mass on pulley A diagram would be very helpful.