Not compatible units

Prime usually is right when it moans about incompatible units.

But your picture does not show enough information. Whenever possible you should attach the worksheet itself and also state which version of Prime you are using (especially if you are not using the latest version).

You have a sum with three summands and to able to add all of them, they all must be of the same dimension. The error message indicates that this is not the case. The second summand clearly is of dimension force, but we don't see the unit of gamma and the unit of N.ed.

The actual unit does not matter, its the dimension that matters. gamma must have 1/force and N.ed must be force.

Whether the force unit used is N, kN, lbf, or ... does not matter.

Chances are that gamma is not of dimension 1/force and so Prime refuses to add 1/gamma and a force (the second summand).

As Werner_E says, the units are not compatible with each other, given that all terms in the equation must be expressed in N. Likewise, 2 arguments are unknown, so reverse engineering was performed, where the remaining values could be tentatively determined.

A picture is not always equal to a 1000 words - therein lies your problem

Hi @BV_12977118,

I wanted to see if you got the help you needed.

If so, please mark the appropriate reply as the Accepted Solution. It will help other members who may have the same question.
Please note that industry experts also review the replies and may eventually accept one of them as solution on your behalf.
Of course, if you have more to share on your issue, please pursue the conversation. 

Thanks,
Anurag