Some engineers have developed a device that provides lighting to rural areas with no access to grid electricity. The device is i
ntended for indoor use. It is driven by gravity, and it works as follows: A bag of rock or sand is raised by human power to a higher location. As the bag descends very slowly, it powers a sprocket-wheel which also rotates slowly. A gear train mechanism converts this slow motion to high speed, which drives a DC generator. The electric output from the generator is used to power an LED bulb. Consider a gravity-driven LED bulb that provides 16 lumens of lighting. The device uses a 10-kg sandbag that is raised by human power to a 2-m height. For continuous lighting, the bag needs to be raised every 20 minutes. Using an efficacy of 150 lumens per watt for the LED bulb, determine (a) the velocity of the sandbag as it descends and (b) the overall efficiency of the device.
1 answer:
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Answer:
Check the explanation
Explanation:
Points to consider:
We need to take the input from the user
We need to find the manhatan distance and euclidian using the formula
(x1, y1) and (x2, y2) are the two points
Manhattan:
Euclidian Distance:
Code
#include<stdio.h>
#include<math.h>
struct Point{
int x, y;
};
int manhattan(Point A, Point B){
return abs(A.x - B.x) + abs(A.y- B.y);
}
float euclidean(Point A, Point B){
return sqrt(pow(A.x - B.x, 2) + pow(A.y - B.y, 2));
}
int main(){
struct Point A, B;
printf("Enter x and Y for first point: ");
int x, y;
scanf("%d%d", &x, &y);
A.x = x;
A.y = y;
printf("Enter x and Y for second point: ");
scanf("%d%d", &x, &y);
B.x = x;
B.y = y;
printf("Manhattan Distance: %d\n", manhattan(A, B));
printf("Euclidian Distance: %f\n", euclidean(A, B));
}
Sample output
Answer:
You need a 120V to 24V commercial transformer (transformer 1:5), a 100 ohms resistance, a 1.5 K ohms resistance and a diode with a minimum forward current of 20 mA (could be 1N4148)
Step by step design:
- Because you have a 120V AC voltage supply you need an efficient way to reduce that voltage as much as possible before passing to the rectifier, for that I recommend a standard 120V to 24V transformer. 120 Vrms = 85 V and 24 Vrms = 17V = Vin
- Because 17V is not 15V you still need a voltage divider to step down that voltage, for that we use R1 = 100Ω and R2 = 1.3KΩ. You need to remember that more than 1 V is going to be in the diode, so for our calculation we need to consider it. Vf = (V*R2)/(R1+R2), V = Vin - 1 = 17-1 = 16V and Vf = 15, Choosing a fix resistance R1 = 100Ω and solving the equation we find R2 = 1.5KΩ
- Finally to select the diode you need to calculate two times the maximum current and that would be the forward current (If) of your diode. Imax = Vf/R2 = 10mA and If = 2*Imax = 20mA
Our circuit meet the average voltage (Va) specification:
Va = (15)/(pi) = 4.77V considering the diode voltage or 3.77V without considering it
Answer:
A.) 0.3088
B.) 0.0017
C.) part A
Explanation:
A.)
B.)
C.) Since the seat performance for an individual pilot is more important than 39 different pilots.