D. the motion of the source or observer
The pairs of triangles that can be proven congruent by the hl theorem is the right angled triangle.
<h3>What is mearnt be the HL theorm?</h3>
The HL theorem is also known as the Hypothenus Leg theorem, it states that "the hypotenuse and leg of one right triangle are congruent to the hypotenuse and leg of another right triangle, then the two triangles are congruent."
Learn more about the postulates of the HL theorem here:
brainly.com/question/25922842

Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them. The forces along the line joining the centre of the two objects.
❍ Let us consider two masses m1 and m2 line at a separation distance d. Let the force of attraction between the two objects be F.
According to universal law of gravitation,

Also,

Combining both, We will get

Or, We can write it as,

Where, G is the constant of proportionality and it is called 'Universal Gravitational constant'.
☯️ Hence, derived !!
<u>━━━━━━━━━━━━━━━━━━━━</u>
This is problem of free falling
objects, which can be solved using the formula:
V = sqrt(2gy)
Where v is the velocity upon
impact
G is the acceleration due to
gravity ( 9.81 m/s2)
Y is the height
Since Venessa is 3.5 m
Y = 30 -3.5 = 26.5 m
V = sqrt(2 (9.81 m/s2) ( 26.5
m))
<span>V = 22.8 m/s</span>
The 'net' force acting on the box is (9 - 3) = 6 newtons
in the direction that Carlos is pushing.
Force = (mass) x (acceleration)
6 = (3) x (acceleration)
Divide each side by 3 :
<em>2 m/s² = acceleration</em>