5. Two 400 g blocks are connected by a rigid rod. The Blocks can rotate freely at the ends of the rod, so the rod does not apply any moments to the blocks. The blocks are in contact with the wall and floor, and can slide without friction. The system is released from rest when X=24cm and Y=18cm. Ignore the mass of the rod. What are the initial accelerations of Block A and Block B just after being released? Hint: See Assignment 4, Problem 2 for help getting a relationship between the acceleration of Block A and the acceleration of Block B. Y m = 400 g A | L g I 1 I I X B m = 400 g

The momentum of the force F = -100 i -70 j + 50 k around the point O is MO = 410 i- 300 j + 400 k, Determine the coordinates of the point through which the line of actionof F intercepts the yz plane.

Average sludge production reported by members of the National Association of Clean Water Agencies is 0.7 tons of sludge TS per MG wastewater treated. Assume that the organic matter (VS) in the sludge contains 10% N and that the ratio of VS/TS in sludge is 0.85. A) How many mg/L of N are removed from the wastewater due to assimilation? B) If the raw wastewater contained 50 mg/L total N, what percent was removed via assimilation? C) Why is this a disappointing result in terms of nutrient recovery and reuse goals?

The two-part curve is from a BOD bottle test conducted over 50 days (i.e., ultimate UBOD). The nitrifying bacteria numbers grew to significance by Day-8.There is a lower cBOD curve and an upper nBOD curve. BOD₁ = UBOD (1− e−k₁t) A) What is the rate constants k for cBOD? B) What is the rate constants k for nBOD? C) Why aren't nitrifiers prevalent in the raw wastewater? Treatment ponds have long hydraulic residence times (HRTs), so nitrifiers are a significant part of the microbiome. D) Sketch a 50-d BOD curve similar to the above, but for a pond effluent sample. The sum of the c and n BODs at 50 days is 30 mg/L. E) Why does your curve have the shape you give it? 100 80 BOD, mg/L 60 60 40 40 20 20 0 0 10 20 30 40 40 Time, d 50 60

6-19 Determine the LRFD design strength and the ASD allowable strength of the section shown if snug-tight bolts 3 ft on center are used to connect the A572-Grade 50 angles. The two angles, 5×31/2 × 5/16, are oriented with the long legs back-to-back (2 L5 × 31/2 × 5/16 LLBB) and separated by 3/8 inch. The effective length, (Lc)x = (Lc)y = (Lc)z = 14 ft. (Ans. 65.4 k LRFD; 43.5 k ASD) Figure P6-19 x x 2L5×32×5/16 LLBB

6-21 Four 3×3× 1/4 angles are used to form the member shown in the accompanying illustration. The member is 24 ft long, has pinned ends, and consists of A572-Grade 50 steel. Determine the LRFD design strength and the ASD allowable strength of the member. Design single lacing and end tie plates, assuming connections are made to the angles with 3/4-in diameter bolts. (Ans. 159.1 k LRFD; 106.0 k ASD) Figure P6-21 12 in L 12 in

1000 th 2' 2' w=200 to /ft Handout Problem #3. A beam has the loading and cross section shown. 1) Draw the shear force and bending moment diagrams for the beam. 5" 2) Determine the maximum bending stress in the beam. Carefully identify its location both along the beam and along the cross section. 3) Determine the maximum transverse shear stress in the beam. Carefully identify its location both along the beam and along the cross section: y=2" up from bottom "INA = 33.33 int VMAX = 1160+b MMAX - 2704 Hb-ft QMAX = 8mm³

Units: lb-ft Handout Problem #2 The dimensions of the shape as well as the bending moment diagram of a flanged wooden shape are shown. Determine: (a) the maximum tensile bending stress at any location along the beam and (b) the maximum compressive bending stress at any location along the beam. 10 in. 10,580 9,200 4,743 2 in. 8 in. 2 in. 2 in. -8,400 6 in.

(USE 0BC 2024) For a 800 m2 4-storey sprinklered Dry-cleaning establishment (not using explosive solvents), facing 1 street(s), what are the minimum required fire-resistance ratings (FRR) or fire-protection ratings (FPR) for the following?     Typical floor assembly (in minutes, please. Just write the number of minutes please)           Detailed OBC reference =         Public corridor wall (in minutes please)         Detailed OBC reference =         Suite egress door (in minutes, please) =         Detailed OBC reference =         Exit stair walls (in minutes, please) =         Detailed OBC reference =         Exit stair door (in minutes, please) =         Detailed OBC reference =         Elevator shaft enclosure (in minutes, please) =         Detailed OBC reference =         Vertical mechanical shaft enclosure (in minutes, please) =         Detailed OBC reference =