What criteria do you think should be used to determine if someone is an expert in
their field in order to testify in court?

According to Federal Rule of Evidence 702, expert witnesses must have “knowledge, skill, experience, training, or education” which will “help the trier of fact to understand the evidence or to determine a fact in issue.” This is a very broad standard.

force tends to be low and long diustance masses are high

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards