Answer:
minimum power should be used to operate the air conditioner is 4000 W
Explanation:
given data
students n = 160
power p = 125 W
COP = 5.0
to find out
what minimum power should be used
solution
we know the COP formula that is given below
COP = students × power / minimum power
minimum power = n × p / COP
put all value
minimum power = n × p / COP
minimum power = 160 × 125 / 5
minimum power = 4000 W
minimum power should be used to operate the air conditioner is 4000 W
Velocity =
(distance between start point and end point, regardless of the route traveled) / (time spent traveling).
That distance (called the "displacement"), is 10 meters, and almost exactly 1 hour is almost exactly 3,600 seconds. So the numerical value of the velocity during that time is
(10) / (3,600) = almost exactly 0.00278 m/s
= 2.78 x 10^-3 m/s.
The area of the top and bottom:
2πr²
Cost for top and bottom:
2πr² x 0.02
= 0.04πr²
Area for side:
2πrh
Cost for side:
2πrh x 0.01
= 0.02πrh
Total cost:
C = 0.04πr² + 0.02πrh
We know that the volume of the can is:
V = πr²h
h = 500/πr²
Substituting this into the cost equation to get a cost function of radius:
C(r) = 0.04πr² + 0.02πr(500/πr²)
C(r) = 0.04πr² + 10/r
Now, we differentiate with respect to r and equate to 0 to obtain the minimum value:
0 = 0.08πr - 10/r²
10/r² = 0.08πr
r³ = 125/π
r = 3.41 cm
Answer:
B
Explanation:
A square of frequency of consists of the infinite sum of sine waves, whose frequencies are the odd multiples of the main frequency f i.e f, 3f,5f, 7f, ... . Given that the range of frequencies, to which the system responds is 20-40 kHz, for a square wave of frequency 10kHz we need to look for the harmonics whose frequencies are in the systems' respond range, which are the harmonics of 20, 30 and 40 kHz
Because weight W = M g, the ratio of weights equals the ratio of masses.
(M_m g)/ (M_w g) = [ (p^2 Man )/ (2 K_man)] / [ (p^2 Woman )/ (2 K_woman)
but p's are equal, so
K_m/K_m = (M_w g)/(M_m g) = W_woman / W_man = 450/680 = 0.662