I agree with your statement, a way to check if a force is conservative is to check whether its curl is zero, but in this case, it obviously cannot be zero since the force is tangential to a circular path at all points along the path, implying that it "swirls" about the origin. Also, by checking...
Start with kinematic equations for position as a function of acceleration and initial velocity. Since the problem does not specify a time of flight, you must solve these equations to be time-independent. Essentially, just find an equation for ##t## and plug it into the other equation and solve...
I believe that your thinking for the first picture is correct. Obviously, gravity must be acting upon both of the objects, and likewise, since both ##A## and ##B## are resting on surfaces, they must be experiencing some normal force. Now, we know from the figure that ##F## is applied to ##B##...
Notice that ##A^2 = A \cdot A##. When the gradient operator is applied to this term, you get two terms looking like this: ##A(\nabla A)##. In your initial work, you only have one of these terms, so to account for the duplicate, you must divide ##\nabla A^2## by two, which results in the term...