1. Conceptual Questions (1 pt) a) In lecture 5c (MRI) we introduced the idea of an alternating magnetic field B1. Why must the direction of the pulse B1 be alternated? At what frequency must this oscillation occur? Does this frequency depend on B1? b) Briefly explain how to use the right-hand rule in the following situations (i. e. what to do with your right hand): i. When performing the cross product �⃗ = �⃗ × �(⃗. ii. Find the direction of the magnetic field produced by a current-carrying wire. iii. Find the direction of the magnetic field, given the direction of the electrical current in a circular loop

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

An object resting on a table weighs 100 n. with what force is the object pushing on the table? with what force is the table pushing on the object? explain how you got your answer.

The amount of potential energy possessed by an elevated object is equal to what?