An object of mass 1.2 kg is attached to a string of 0.83 m. When this object is rotated around in a horizontal circle with a constant speed, it completes 15 rotations in 9.6 seconds. Calculate a. period (T) of this motion
b. speed of the object
c. tension on the string

An electric power distributor charges residential customers $0.10 per kilowatt-hour (kwh). the company advertises that "green power" is available in 150 kwh blocks for an additional $4 per month. (green power is generated from solar, wind power, and methane sources.) if a certain customer uses an average of 391 kwh per month and commits to one monthly 150 kwh block of green power, what is her annual power bill