2. What gravitational attraction does the moon have on the earth? (mass of earth is 6 x 102 kg, mass of moon is 7.4 x 1022 kg and distance between earth and moon is 3.8 x 10 m).

Given that,

Mass of the Earth m

1

=6×10

24

Kg

Mass of the Moon m

2

=7.4×10

22

kg

Distance between the Earth and the Moon d=3.84×10

5

km=3.84×10

8

m

Gravitational Constant G=6.7×10

−11

Nm

2

/kg

2

Now, by using Newton’s law of gravitation

F=

r

2

Gm

1

m

2

F=

(3.84×10

8

)

2

6.7×10

−11

×6×10

24

×7.4×10

22

F=

14.8225×10

16

297.48×10

35

F=20.069×10

19

F=20.1×10

19

N

Hence, the gravitational force of attraction is 20.1×10

19

N

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.

i think its c if i'm wrong