Before electric hybrid cars, one way that had been suggested for storing the braking energy is to store it in the ke of a spinning mass. the moment of inertia for a hollow cylinder has an inner radius of 7/8 of the otter radius is .9mr^2, where m is the mass of the cylinder and r is simply the radius.
a. what angular velocity in radians per second would be needed to in the spinning cylinder of iron with a mass of 60kg, radius of .20m to store 200,000 joules of energy? what is this in revolutions per minute?
b. torque needed to be applied to the cylinder by the coupling mechanism if 2 joules from above were to be achieved in 1 second at constant acceleration?
c. what would we need to do if we wanted to reduce the weight of the hollow cylinder and keep the energy storage? what is one engineering problem that would need to be addressed on strain limits of materials and forces in rotation objects?

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 starts from rest at point f and speeds up continuously as it moves around an oval. a. choose a point about 1/8 th of the way around the oval from point f, and label it point g. draw a vector to represent the velocity of the object at point g. b. determine the change in velocity vector   between points f and g.

James is trying to prove newton's 2nd law of motion. he tries to move four different objects with different masses, shapes, and sizes from point a to point b. the objects are a toy car, a car, a refrigerator, and a kitchen table. after some experimentation, he finds that force is dependent on the mass of the object, rather than it's size or shape. the object that takes the most force to move is the