It should be S since S stands for students. Giving the team with more members the upper hand. Hope this helps.
Answer:
a). Determine the magnitude of the gravitational force exerted on each by the earth.
Rock: 
Pebble: 
(b)Calculate the magnitude of the acceleration of each object when released.
Rock: 
Pebble: 
Explanation:
The universal law of gravitation is defined as:
(1)
Where G is the gravitational constant, m1 and m2 are the masses of the two objects and r is the distance between them.
<em>Case for the rock </em>
<em>:</em>
m1 will be equal to the mass of the Earth
and since the rock and the pebble are held near the surface of the Earth, then, r will be equal to the radius of the Earth
.

Newton's second law can be used to know the acceleration.

(2)

<em>Case for the pebble </em>
<em>:</em>


Answer:
B v1= 12.5m/s
Explanation:
As the acceleration is constant and time taken is also same and distance covered is halfed so the speed will also be halfed.
Answer:
(h₁-h₂) = 2.30 10² m
Explanation:
The pressure depends on the height with the formula
P = P_atm + rho g h
Let's apply this expression for the building
P₁ = P_atm + rho_air g h₁
P₂ = P_atm + rho_air g h₂
Subtract
P₁ - P₂ = roh_air g (h₁ –h₂)
The measured pressure is in mm Hg to take this unit to units of pressure must be multiplied by the density of mercury and the acceleration of gravity
P₁- P₂ = rho_Hg g (h₁-h₂) _Hg
rho_Hg g (h₁-h₂) _Hg = roh_air g (h₁ –h₂)
(h₁ –h₂) = rho_Hg / rho_air (h₁-h₂) _ Hg
Let's calculate
(h₁-h₂) = 13600 / 1.18 (695-675)
(h₁-h₂) = 2.30 10⁵ mm
Let's reduce to meter
(h₁-h₂) = 2.30 10⁵ mm (1 m / 10³ mm)
(h₁-h₂) = 2.30 10² m