Answer:
B) 16.67
Explanation:
If the dimension of one lumber is 2" × 6", the total area of one lumber will be 12inch²
If the total board feet of lumber there is 200in, therefore the total board of lumber that will be needed is 200/12 which gives 16.67 lumbers
Answer:

Explanation:
The mass of one electron is

So the number of electrons contained in M=1.7 kg of mass is

The charge of one electron is

So, the total charge of these electrons is equal to the charge of one electron times the number of electrons:

Answer:
F=94.32*10⁻⁹N , The force F is repusilve because both charges have the same sign (+)
Explanation:
Two point charges (q₁, q₂) separated by a distance (d) exert a mutual force (F) whose magnitude is determined by the following formula:
F=K*q₁*q₂/d² Formula (1)
F: Electric force in Newtons (N)
K : Coulomb constant in N*m²/C²
q₁,q₂:Charges in Coulombs (C)
d: distance between the charges in meters(m)
Equivalence
1nC= 10⁻⁹C
Data
K=8.99x10⁹N*m²/C²
q₁ = 7.94-nC= 7.94*10⁻⁹C
q₂= 4.14-nC= 4.14 *10⁻⁹C
d= 1.77 m
Magnitude of the electrostatic force that one charge exerts on the other
We apply formula (1):

F=94.32*10⁻⁹N , The force F is repusilve because both charges have the same sign (+)