A boy swings a ball on a string at constant speed in a circle that has a circumference equal to 6 m. What is the work done on the ball by the 10 N tension force in the string during one revolution of the ball

0 J

Explanation:

From the diagram below; we would notice that the Force (F) = Tension (T)

Also the angle θ adjacent to the perpendicular line = 90 °

The Workdone W = F. d

W = Fd cos θ

W = Fd cos 90°

W = Fd (0)

W = 0 J

Hence the force is perpendicular to the direction of displacement and the net work done in a circular motion in one complete revolution is = 0

0.11 m/s and 0.28 m/s should be correct

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.