Recent content by taxidriverhk

I think I had included the weight of the beam in FBD and equations, but maybe NTW is trying to tell me that the weight should be in another point along the beam?

Homework Statement [Ans: FA = -206i + 188j lb, T = 131 lb] Homework Equations Since it's assumed that the system is in equilibrium, so I assume that ΣF=0 and ΣM=0 The Attempt at a Solution I tried to draw a free-body diagram for the system, and set up three equations below: (I don't know...

So the final concentration of each ion is below Ba2+ = 0 M SO42- = 0.0004 M Na+ = 0.0120 M NO3- = 0.0120 M is it right? If they are right, then I will be able to find the initial concentration of Ba(NO3)2 by first finding the number of moles of NaNO3, and use the chemical equation to convert it...

I think I may get some ideas from what you asked I now try to write out the net ionic equation for the reaction below Ba2+ + 2NO3- + 2Na+ + SO42- → BaSO4 + 2Na+ + 2NO3- And I find out that NO3- and Na+ are spectator ions, that means their concentrations did not change right? But the problem...

Homework Statement Given balanced chemical reaction: Ba(NO3)2 (aq) + Na2SO4 (aq) → BaSO4 (s) + 2NaNO3 (aq) Suppose 200 mL of Ba(NO3)2 and 200 mL of Na2SO4 of unknown concentrations are mixed together and forms the reaction above. Then, there are 0.0120 M of NaNO3 produced, and 0.0004 M of...

Homework Statement Assume there is a person sitting on a stool that is free to rotate, the person holds a wheel in which its center of mass is directly above the center of mass of the person plus the stool, then the person rotates the wheel counterclockwise at 6π rad/s. Suddenly, the person...

You are trying to prove that det(λI - B) = det(λI - A) and there is basically no way to prove that B = A because they are really not equal to each other You are given a hint that λI = CλIC-1 and B = CAC-1 then you substitute these two into det(λI - B) you should be able to prove that det(λI -...

Sure, the limits of et and t as t approaches 3 are not equal, so f(t) should not be piece-wise continuous, isn't that right?

Homework Statement Let f(t) = t if 0<t<3 et if t>3 a. Is f(t) piece-wise continuous? b. Is f(t) of exponential order α? Either prove it by producing an M, T and α that satisfies the definition, or show that no such constants exist. c. Does the Laplace transform of f(t) exist...

Homework Statement Consider the figure below, a ball of mass m=0.100 kg tied by a string of 0.100 m travels in a circular motion with 2 revolutions per second. Find the angle θ that keeps the ball stationary. Given: m = 0.100 kg, v = 2 rev/sec L = 0.100 m (radius?)...