Question

What E is. if E=2 when W=15, find E when W=10

Answer 1

Since the elongation E varies directly with the weight W, they are related as follows

`E=kW`

where k is the constant of proportionality. In order to find k, we can substitute the given values, that is, when E=2, W=15, then we have

`2=k\cdot15`

Then, k is given as

`k=(2)/(15)`

Therefore, our formula for any E and W is

`E=(2)/(15)W`

Now, in order to find E in the second case, by replacing W=10, we get

`E=(2)/(15)(10)`

which yields

`E=(20)/(15)=(4)/(3)`

Therefore, the answer is

`E=(4)/(3)`