Guardrail systems must be capable of withstanding at least 200 pounds of force applied within 2 inches of the top edge, in any direction and at any point along the edge, and without causing the top edge of the guardrail to deflect downward to a height less than 39 inches above the walking/working level.
Answer:
Explanation:
Solution:
- We are to develop a circuit that has an input of available battery 9.0 V and has an output potential difference of 3.0 V
- We are given:
Battery ..... 9.0 V
Resistors ... 10 Kohms
- We will develop a potential divider circuit by placing a few resistors in series and then connecting in between resistors to get our desired voltage.
- How many resistors should we use ?
We know that if we add series resistance in a circuit the current decreases proportionally. However, the potential difference across resistors also changes.
- Our desired voltage is a ratio of input battery voltage.
Input / Output = 9 / 3 = 3
We can use this ratio as the number of "Identical resistors" that can be placed in series to give us the desired voltage. Note: This would not be true if we did not had any identical resistors.
- We will place 3, 10 Kohms resistors in series.
- To verify we will calculate the potential difference across each resistor. The current of the total circuit is:
I = V / R_eq
R_eq = 3*R = 30 kohms
I = 9 / 30,000 = 0.0003 Amps
- Now the potential difference for each resistor:
V = I*R_each
V = 0.0003*(10,000)
V = 3.0 V
- We can take two leads across any 10 kohms resistor and the potential difference across the leads would be the desired voltage 3.0 V.
Answer:
-36 m
Explanation:
In the diagram, the front of the black car is used as reference point which is point 0. The distance from the black car to the front of the red car is 15 m while the distance from the black car to the white van is - 21 m. The negative sign means the white van is behind the black car.
If the red car is used as the reference (point 0), the distance from the black car to the red car would be -15 m and the distance from the black car to the white van would be -21 m. Hence:
Distance from red car to white van = distance from the black car to the red car + distance from the black car to the white van = -15 + (-21)
Distance from red car to white van = -15 - 21 = -36 m
