<span>light amplification by stimulated emission of radiation
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ANSWER:
250 J
STEP-BY-STEP EXPLANATION:
F = 20N is required to stretch the spring by 4 meters
We know that the force is equal to:

We solve for k (spring constant):

The work done in stretching the spring is given by the following equation (in this case the stretch is 10 meters:

The work required is 250 joules.
Answer:
The word Allopatric is derived from the Greek words allos = other and Patris = fatherland. Allopatric specification happens when the biological population of the same specie got separated from one another such that it stopped their gene flow or gene migration. It happens due to the geographical changes such as the movement of continents, changes in glaciers, mountains or oceans and it could be happened because of human activities like agriculture and industrial development etc. The first step of Allopatric specification is Geographical isolation. The species got separated and the long distances makes them unable to interbreed.
Predictive maintenance - vibration analysis.
Condition-based maintenance - monitoring pressure reading on Equipment with water systems.
Scheduled maintenance - occurring at repeating intervals is changing a bearing on a conveyor belt every 30 days or inspecting the condition of a motor every 90 days.
Hoping it helps!
A). The drawing looks like a ladder with 4 rungs.
One rung is a 90-volt battery.
The other 3 rungs are the 3 resistors.
b). The equivalent resistance is the reciprocal of (1/15 + 1/30 + 1/60).
That's the reciprocal of 7/60, or about 8.571... ohms.
c). I = V/R = 90 / 8.571... = 10.5 Amperes.
d). The 60-ohm resistor is connected directly across the battery.
Power = V²/R = (90²) / 60 = 135 watts. Better COOL that baby !