To find the magnitude of the normal force, you must express fn in terms of fw since ff is an unknown. using the equations you found in the two previous parts, find an expression for fn involving fw and θ but not ff. cosθff - sinθfn = 0ffsinθ + fncosθ - fw = 0

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve