An elastic spring of length 20cm stretches by 7mm undergoes a strain of 0.02 under load of 20n, the natural length of the spring is?
To find the natural length of the spring, we can use Hooke's Law, which states that the strain in an elastic material is directly proportional to the stress applied to it. In this case, we are given the strain (0.02) and the load (20N), and we need to find the natural length of the spring.
The formula for strain is given by:
strain = (change in length) / (original length)
Here, we are given the change in length (7mm), so we can rearrange the formula to solve for the original length of the spring:
original length = (change in length) / strain
Let's substitute the values into the equation:
original length = 7mm / 0.02
To perform the calculation, we need to convert the units to the same measurement. We can convert 7mm to meters by dividing it by 1000:
original length = (7 / 1000)m / 0.02
Now, we can calculate the original length of the spring:
original length = 0.35m / 0.02
original length = 17.5m
Therefore, the natural length of the spring is 17.5 meters.