Answer:

Explanation:
The magnitude of the gravitational force between two objects is given by the equation:

where
G is the gravitational constant
m1, m2 are the masses of the two objects
r is the separation between the objects
The gravitational force is always attractive.
In this problem, we have:
is the mass of the Earth
is the mass of the Moon
is the separation between the Earth and the Moon
Therefore, the gravitational force between them is

Answer:
2.43J
Explanation:
Given parameters:
Mass of the arrow = 0.155kg
Velocity = 31.4m /s
Unknown:
Kinetic energy when it leaves the bow = ?
Solution:
The kinetic energy of a body is the energy in motion of the body;
it can be derived using the expression below:
K.E =
m v²
m is the mass
v is the velocity
Solve for K.E;
K.E =
x 0.155 x 31.4 = 2.43J
One of the major limitations of using the ball and stick model for DNA, is that within a single double stranded segment of DNA, one would have to use many many balls to represent atoms that are present in the sugar phosphate backbone, along with all of the main atoms that compose the nitrogenous bases of DNA, we also cannot construct or show the helical form of DNA, by using balls and sticks as well.
D = distance between th two trains at the start of the motion = 100 miles
V = speed of the faster train towards slower train = 60 mph
v = speed of the slower train towards faster train = 40 mph
t = time taken by the two trains to collide = ?
time taken by the two trains to collide is given as
t = D/(V + v)
t = 100/(60 + 40) = 1 h
v' = speed of the bird = 90 mph
d = distance traveled by the bird
distance traveled by the bird is given as
d = v' t
d = 90 x 1
d = 90 miles