Recent content by zspdztzx

Homework Statement A truss is made by hinging two uniform, 150-N rafters as depicted in the diagram below. They rest on an essentially frictionless floor and are held together by a horizontal tie rope. A 500-N load is held at their apex. Find the tension in the rope. Homework Equations...

Ahh I see. That helps! Thank you so much Dr.! :)

The vector sum will be 5N to the right. So the tension is 5N to the right? AND, what if the two stretching forces are equal in magnitude but opposite in direction? 10N to the left, and 10 to the right? In that case, the vector sum is 0N, but obviously, there's still tension on the string...

Homework Statement If a string is being pulled to the left by 10N and at the same time being pulled to the right by 15N, what is the tension on the string? Homework Equations N/A The Attempt at a Solution I always think tension as the force towards one end of the string that...

My colleague and I were writing the standard operating procedures today for some radioimmunoassays that we will be doing in October. Radioactive decay, tracer half-life calculation, tracer concentration calculation, Gamma-ray CPM calculation, radiation safety, etc.. All related to physics! And...

Hi there! This sounds like a rotational equilibrium problem! Below is my rationale - 1) Set a horizontal axis zero point at the left end-point of the rod. Therefore, we have the center of gravity of the rod at 100cm, and we have the point of upward force at 185cm. 2) Set the point of rotation...

Your rationale is correct! However, I have a few minor suggestions - 1. For A), B), and C), I agree with ehild, there are rounding problems. My results for A) are 1.23s (for g=-10) or 1.24s (for g=-9.8). 2. For C), why not using Vyfinal=Vyinitial-g*t? I think this makes calculation easier...

Thank you so much Dr.! Now it makes sense! I think the reason I couldn't understand this before was I always assumes that the actual pivot point "moves" with different ways of torque calculation! After all, the physical pivot for the seesaw is still at the same location but the imaginary...

Hi! Here are my two cents! If there is no heat loss or particle loss in this process, then given the pressure is constant, therefore internal energy of the gas, delta-U, is zero, which, translates to, heat that flowed in, delta-Q, equals to W, the work done by the gas (i.e. expansion)...

Homework Statement Why, for any system that is in rotational equilibrium, the torque about 1) any point on the object or 2) any point in space, must be zero.Homework Equations N/AThe Attempt at a Solution What I do not understand is, why the torque about ANY point on the object is zero...