Which of the following describe an electric motor? Check all that apply.
A. Uses the interaction between a spinning coil of wire and a magnet
B. Can be powered by a hand crank
c. Changes mechanical energy to electrical enggy
D. Is found in many appliances with moving parts, like a vacuum
cleaner or a blender

C. Changes mechanical energy to electrical

i think the answer would be b

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.