Newton’s Third Law of Motion states that when one object exerts a force on a second object, the forces are __________________.
1 answer:
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Answer:
a) 842.8 N
b) 529.2 N
Explanation:
Given
Mass of scaffold, m = 60 kg
Length of scaffold, l = 5 m
Mass of window washer, m(w) = 80 kg
Distance of the window washer, d = 1.5 m
From the attached image
a = 1.5 m
b = 2.5 m
c = 5 m
W = 60 * 9.8 = 588 N
W(w) = 80 * 9.8 = 784 N
Since the scaffold is in equilibrium, then
Στ(b) = 0
W * (c - b) + W(w) * (c - a) - Lc = 0
Lc = W * (c - b) + W(w) * (c - a)
L = [W * (c - b) + W(w) * (c - a)] / c
L = [588 * (5 - 2.5) + 784 * (5 - 1.5)] / 5
L = (588 * 2.5 + 784 * 3.5) / 5
L = (1470 + 2744) / 5
L = 4214 / 5
L = 842.8 N
Στ(a) = 0
Rc - W * b - W(w) * a = 0
R = [W * b + W(w) * a] / c
R = (588 * 2.5 + 784 * 1.5) / 5
R = (1470 + 1176) / 5
R = 2646 / 5
R = 529.2 N
Answer:
Formal charge for the first resonance structure of NO₂; first Oxygen = 0, N = +1, second Oxygen = -1
Formal charge for the second resonance structure of NO₂; first Oxygen = -1, N = +1, second Oxygen = 0
Explanation:
The formal charge of an atom in a molecule is the assumed charge the atom would have if the electrons in the bonds are redistributed evenly between the atoms.
Formal charge = valence electrons - (non-bonding electrons) - (bonding electrons / 2).
For NO₂ molecule, the formal charges for the atoms are as follows;
First Oxygen atom = 6 - 4 - 4/2 = 0
For Nitrogen = 5 - 1 - 6/2 = +1
For the second Oxygen atom = 6 - 6 - 2/2 = -1.
Overall charge = 0 + (+1) + (-1) = 0
For the second resonance structure,
First Oxygen atom = 6 - 6 - 2/2 = -1
For Nitrogen = 5 - 1 - 6/2 = +1
For the second Oxygen atom = 6 - 4 - 4/2 = 0
Overall charge = (-1) + (+1) + (0) = 0
Note: Where resonance structures for atoms or ions exist, the formal charges of each of the respective atoms or ions are calculated according.
