일반물리학 1 — Force and Motion-I: Problem 48

48 In Fig. 5-34, elevator cabs A and B are connected by a short cable and can be pulled upward or lowered by the cable above cab A. Cab A has mass 1700 kg; cab B has mass 1200 kg. A 12.0 kg box of catnip lies on the floor of cab A. The tension in the cable connecting the cabs is $1.91 \times 10^4$ N. What is the magnitude of the normal force on the box from the floor?