A1-horsepower, 24-volt dc electric motor that is 80 percent efficient requires 932.5 watts. how much power will a 1-horsepower, 12-volt dc electric motor that is 75 percent efficient require?

A 1 horsepower motor with 75% effiency will require 994. 26 watt

Explanation:

To calculate the effiency, 1 horsepower is equivalent to 745.7 watts

1hp= 745.7 w

So, by using a rule of three the calculation its like this:

745.7  ⇒  100%

X        ⇒  75%

The information about the volts in this example is not required, but it can be used to calculate the current.

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.