Answer:

Explanation:
Given the forces:
F1 = 8.92 i + 17.37 j
F2 = 8.31 i - 10.97 j
If a third vector is added to them such that they add up to to the null vector as F1 + F2 + F3 = 0
then to get F3:
F3 = -F2-F1
F3 = -(8.31 i - 10.97 j)-(8.92 i + 17.37 j
)
F3 = -8.31 i + 10.97 j-8.92 i - 17.37 j
F3 = -8.31i-8.92i+10.97j-17.37j
F3 = -17.23i-6.4j
from the vector:
x = -17.23 and y = -6.4
angle of the third vector with respect to the +x-axis is expressed as:

Hence the angle the vector makes with the x axis will be 
Answer:
Mass of natural gas needed to heat the room is 350,000BTUs
Explanation:
The heating efficiency of a furnace is never 100% because not all energy is released and not all heat is available to heat the place. A lesser efficiency requires more consumption of fuel. Heating values are used for heating fuels in order to calculate the mass of fuel needed.
The heating value of natural gas is 1,000,000BTUs
Therefore the formular for calculating mass of natural gas needed= Heating value of natural gas×efficiency.
Mass=1,000,000×0.35
Mass=350,000BTUs
Answer:
0.480 seconds
Explanation:
The period is the time for 1 revolution. Writing a proportion:
14.4 s / 30.0 rev = t / 1 rev
t = 0.480 s
The period is 0.480 seconds.