Atoms involved in (polar) covalent bonds do not share their electrons equally.
An action-reaction pair would be a pair in which one of the elements exerts a force on the other element (action), and then the other element would respond to this force by exerting another force in the opposite direction (reaction).
From the given choices, we will see that:
For choice A, the moon exerts a force on the earth by pulling it (action) and the earth responds to this force by pulling the moon (reaction in opposite direction of the action).
Therefore, the correct choice would be:
A. <span>The Moon Pulls on Earth, and Earth pulls back on the moon.</span>
Answer:
q₃=5.3nC
Explanation:
First, we have to calculate the force exerted by the charges q₁ and q₂. To do this, we use the Coulomb's Law:

Since we know the net force, we can use this to calculate q₃. As q₁ is at the right side of q₃ and q₁ and q₃ have opposite signs, the force F₁₃ points to the right. In a similar way, as q₂ is at the left side of q₃, and q₂ and q₃ have equal signs, the force F₂₃ points to the right. That means that the resultant net force is the sum of these two forces:

In words, the value of q₃ must be 5.3nC.
Answer:
1387908 lbm/h
Explanation:
Air flowing into jet engine = 70 lbm/s
ρ = Exhaust gas density = 0.1 lbm/ft³
r = Radius of exit with a circular cross section = 1 ft
v = Exhaust gas velocity = 1450 ft/s
Exhaust gas mass (flow rate)= Air flowing into jet engine + Fuel
Q = (70+x) lbm/s
Area of exit with a circular cross section = π×r² = π×1²= π m²
Now from energy balance
Q = ρ×A×v
⇒70+x = 0.1×π×1450
⇒70+x = 455.53
⇒ x = 455.53-70
⇒ x = 385.53 lbm/s
∴ Mass of fuel which is supplied to the engine each minute is 1387908 lbm/h