(a) Explain the meaning of the terms negative and positive feedback as they apply to amplifier circuits. Briefly describe one application of positive feedback that you have encountered.
(b) Outline three advantages of employing negative feedback in an operational amplifier circuit. Why is it often necessary to reduce the gain of an operational amplifier from its open-loop value?
(c) Derive an expression for the voltage gain of an amplifier employing voltage series negative feedback and thus show that the closed-loop gain is independent of the open- loop gain, provided that certain conditions are obeyed: list the necessary conditions
(d) If the open-loop gain of an amplifier of this type is 4 x 10^5, and the fraction of the output voltage fed back to the input is 0.01, calculate the change in gain of the feedback amplifier if the open-loop gain changes by 30%.

Alandscaper is shopping for landscaping materials. she wants to use materials through which water flows easily. which materials should she choose? check all that apply. clay gravel granite rocks with cracks loosely packed soil

Amoving company collects data about couches they move and displays the data in a table. the force along the ramp, the angle of the ramp, and the height the couch is raised to are shown. which statements correctly compare the work done to move the couches? check all that apply. the same amount of work is done for couches 1 and 3. the same amount of work is done for couches 2 and 3. the work for couch 1 is greater than the work for couch 2. the work for couch 2 is less than the work for couch 3. the work for couch 3 is greater than the work for couch 1. the work for couch 2 is greater than the work for couch 1.

Amass m = 74 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius r = 18.4 m and finally a flat straight section at the same height as the center of the loop (18.4 m off the ground). since the mass would not make it around the loop if released from the height of the top of the loop (do you know why? ) it must be released above the top of the loop-the-loop height. (assume the mass never leaves the smooth track at any point on its path.) 1. what is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track? 2. what height above the ground must the mass begin to make it around the loop-the-loop? 3. if the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop? 4. if the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (18.4 m off the ground)? 5. now a spring with spring constant k = 15600 n/m is used on the final flat surface to stop the mass. how far does the spring compress?