Answer:
490.5 N
Explanation:
Coefficient of friction is 0.5 since friction force is set to halfway between none and lots. Minimum force is given by multiplying the weight and coefficient of friction
F= kN where k is coefficient of friction while N is weight. Also, N=mg where m is mass and g is acceleration due to gravity.
F=kmg=0.5*100*9.81=490.5 N
Bar magnets have 2 poles. I think. Answer: first choice
