So, this variation, the phase variation clearly depicts that. What will happen if you just add this? Approximately close to 100 and this is approximately close to 75. So, you are getting something like 175. But when you have physically added without considering the maximum drag force and inertia force, you see that the variation looks like this. And a total maximum, your maximum force at any given elevation will be, this will be the maximum force. And the phase at which, the maximum force is occurring maximum total force is occurring is neither 90 degrees nor 180 degrees. Understand, it is somewhere in between and this phase angle we need to determine.