Answer:
Restoring force of the spring is 50 N.
Explanation:
Given that,
Spring constant of the spring, k = 100 N/m
Stretching in the spring, x = 0.5 m
We need to find the restoring force of the spring. It can be calculated using Hooke's law as "the force on a spring varies directly with the distance that it is stretched".


F = 50 N
So, the restoring force of the spring is 50 N. Hence, this is the required solution.
In my estimation I would say C, I was leaning towards A, but I believe that would merely be "incomplete combustion." I hope this was semi-helpful!
Because it reverses an image there for making the objects appear on opposite side
Since you are looking for the speed, you need to rearrange the formula which is f = speed / wavelength. That should give you speed = f (wavelength.) All you need to do next is to substitute the value to the following equation. speed = 250 Hz (6.0m) that should leave you with 1500 m/s which is very fast.