Answer:
amount of energy = 4730.4 kWh/yr
amount of money = 520.34 per year
payback period = 0.188 year
Explanation:
given data
light fixtures = 6
lamp = 4
power = 60 W
average use = 3 h a day
price of electricity = $0.11/kWh
to find out
the amount of energy and money that will be saved and simple payback period if the purchase price of the sensor is $32 and it takes 1 h to install it at a cost of $66
solution
we find energy saving by difference in time the light were
ΔE = no of fixture × number of lamp × power of each lamp × Δt
ΔE is amount of energy save and Δt is time difference
so
ΔE = 6 × 4 × 365 ( 12 - 9 )
ΔE = 4730.4 kWh/yr
and
money saving find out by energy saving and unit cost that i s
ΔM = ΔE × Munit
ΔM = 4730.4 × 0.11
ΔM = 520.34 per year
and
payback period is calculate as
payback period = 
payback period = 
payback period = 0.188 year
Answer:
T= 8.061N*m
Explanation:
The first thing to do is assume that the force is tangential to the square, so the torque is calculated as:
T = Fr
where F is the force, r the radius.
if we need the maximum torque we need the maximum radius, it means tha the radius is going to be the edge of the square.
Then, r is the distance between the edge and the center, so using the pythagorean theorem, r i equal to:
r = 
r = 0.5374m
Finally, replacing the value of r and F, we get that the maximun torque is:
T = 15N(0.5374m)
T= 8.061N*m
Answer:
The air resistance on the skydiver is 68.6 N
Explanation:
When the skydiver is falling down, there are two forces acting on him:
- The force of gravity, of magnitude 
, in the downward direction (where m is the mass of the skydiver and g is the acceleration due to gravity)
- The air resistance, 
, in the upward direction
So the net force on the skydiver is:
where
m = 7.0 kg is the mass
According to Newton's second law of motion, the net force on a body is equal to the product between its mass and its acceleration (a):
In this problem, however, the skydiver is moving with constant velocity, so his acceleration is zero:
Therefore the net force is zero:
And so, we have:
And so we can find the magnitude of the air resistance, which is equal to the force of gravity:
Answer:B
Explanation:
Given
speed of car 
mass of clump 
Radius of car tire 
Since the tire is rotating about axle so a centripetal force is acting constantly on each particle towards the center of tire.
Centripetal force is given by
where 
(inward)
Answer:
the element that takes part in a chemical reactions
there are usually two or more reactants in chemical reactions
except decomposition reactions
