Answer:
$1.26
Explanation:
Power =energy/ time
energy =powerxtime
energy =50x31x24=37200
=37.2kwh
1kwh =3.39
37.2kwh=3.39x37.2=126.108cent
=$1.26
Answer:
2.48 m/s
Explanation:
We can use the kinematic equation,
s = ut +½at²
Where
s = displacement
u = initial velocity
t = time taken
a = acceleration
Using the equation in vertical direction,
321 = 0×t +½×g×t², u = 0 because initial vertical velocity is 0
We get t = 8.01 s
Using the equation in the horizontal direction,
52 = u×8.01 +½×0×(8.01)²,. a = 0 because no unbalanced force act on object in that direction
So u = 2.48 m/s
Answer:
15.34 kVA
Explanation:
A motor is a device that converts electrical energy into mechanical energy. It takes in electrical energy at the input and produce torque (motion) at the output.
The power consumption for a three phase motor is the product of voltage and current and √3. The √3 is because it is a three phase supply.
Hence Power (P) =√3 × voltage (V) × current (I)
P = √3 × V × I
Given that voltage (V) = 460 V, current (I) = 17 A. Hence:
P = √3 × V × I = √3 × 460 × 17 = 13544.64 VA
But 1000 VA = 1 kVA. Hence:
The correct options are:
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
<h3>
Why do we radio waves over other electromagnetic waves to transmit information to Earth? </h3>
Radio waves are electromagnetic waves with frequencies on the range from 10 KHz to 10 THz.
Now, remember that all electromagnetic waves have the same speed, which is the speed of light, and the energy of a wave is proportional to its frequency.
Particularly, we can see that radio waves have small frequencies (smaller than infrared light) so these waves carry very little energy.
With that in mind, the correct options are.
D
"Radio waves have a lower frequency, which makes them safer for humans."
B
"Radio waves take less energy to produce."
These are the two main reasons of why we use radio waves.
If you want to learn more about electromagnetic waves.
brainly.com/question/14015797
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Let the cold water go up x degrees.
Let the hot water go down 100 - x degrees.
The formula for heat exchange is m*c*delta t
Givens
Ice
deltat = x
m = 0.50 kg
c = 4.18
Hot water
deltat = 100 - x
m = 1.5 kg
c = 4.18
Formula
The heat up = heat down
0.50 * c * x = 1.5 * c * (100 - x) Divide both sides by c
Solution
0.50 *x = 1.5*(100 - x) Remove the brackets.
0.5x = 150 - 1.5x Add 1.5x to both sides.
0.5x + 1.5x = 150 - 1.5x + 1.5x Combine like terms
2x = 150 Divide by 2
x = 75
Answer
A
