Chapter 3, Problem 70QAP

Assuming an ideal op-amp, design an inverting amplifier with a gain of 25 dB having the largest possible input resistance under the constraint of having to use resistors no larger than 90 kΩ. What's the input resist?

FEA

An American Standard Channel shape must resist a factored tensile load. The length is 15 ft, and there will be two lines of 7/8-in. diameter bolts in the web, as shown in the figure below. Estimate the shear lag factor U to be 0.85. (In a practical design, once the member and bolt layout are selected, the value of U could be computed and the member design could be revised if necessary.) Use A36 steel. For the steel Fy = 36 ksi and F₁ = 58 ksi. Try the tension members given in the table below. Tension member A, (in.²) tw (in.) ry (in.) C10 x 20 5.87 0.379 0.690 C3 × 6 1.76 0.356 0.413 C6 × 8.2 2.39 0.200 0.536 C5 × 9 2.64 0.325 0.486 Bolt lines Select an American Standard Channel shape to resist a factored tensile load of 120 kips. A) C10 × 20 B) C3 × 6 C) C6 x 8.2 D) C5 x 9 -Select- V What is the required gross area? (Express your answer to three significant figures.) Ag = in.2 What is the required effective area? (Express your answer to three significant figures.) Ae = in.2 What is…