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
Hi,
correct answer is {D} 3.5 m/s²
Explanation
Acceleration is the rate of change of velocity with time. Acceleration can occur when a moving body is speeding up, slowing down or changing direction.
Acceleration is calculated by the equation =change in velocity/change in time
a= {velocity final-velocity initial}/(change in time)
a=v-u/Δt
The units for acceleration is meters per second square m/s²
In this example, initial velocity =2.0m/s⇒u
Final velocity=44.0m/s⇒v
Time taken for change in velocity=12 s⇒Δt
a= (44-2)/12 = 42/12
3.5 m/s²
Best Wishes!
KE = kinetic energy
PE = potential energy
GPE = gravitational potential energy
energy is always measured in Joules (J)
KE = (0.5) times the mass times the velocity^2
square the velocity first
Mass = (KE x 2) / v^2
square the velocity first, then double the kinetic energy, then divide
mass is measured in kg
velocity = sqrt(KE x 2 / m)
velocity can be called speed, like in the the second problem
remember to find the square root after you double the KE and divide that by the mass.
for example: if after you doubled KE and divided it by the mass you got sqrt(20), the answer would be about 4.47
GPE = mass x gravitational pull (about 9.8 m/s^2 on earth) x height
height = (PE) / (g x m)
do g x m first
So for question 1:
KE = (0.5)0.1 x 1.1^2
always square the velocity first:
KE = (0.5)0.1 x 1.21
KE = 0.0605
so if you rounded it to the nearest hundreths you would get KE = 0.06 J
don't forget the unit of energy is in Joules
Answer:
Explanation:
We have the following relation between power, P and intensity, I
= 
= 
We also have the following relationship between electric field and electromagnetic radiation thus
Hence 
substituting the values of I, c and e, we have
Answer:
F = 2.01*10^-16N -^k
Explanation:
In order to calculate the magnetic force perceived by the bee, you use the following formula:
(1)
q: charge of the bee = 1pC = 1*10^-12 C
The average speed of a bee and the magnetic field of the earth are:
v = 6.70m/s
B = 30*10^-6 T
The bee is flying to the west (-^i). You consider that the magnetic field direction is to the north (^j). Then, the direction of the magnetic force is:
-^i X ^j = -^k
You replace the values of the parameters in the equation (1), in order to calculate the magnitude of the force:
The magnetic force perceived by the bee is 2.01*10^-16N in the -^k direction, that is, toward the ground
