I need solve this homework of physics ii

A 90-kg man stands in an elevator that has a downward acceleration of 1.4 m/s'. The force exerted by him on the floor is about: OON 0 90 N 0760 N O 880 N Q12 1010 N Three books (X, Y, and Z) rest on a table. The weight of each book is indicated. The force of book Z on book Y is: X 4 N 5 N Z 10 N OON Q13 05N OIN O 14N O 19N A 70-N block and a 35-N block are connected by a string as shown. If the pulley is massless and the surface is frictionless, the magnitude of the acceleration of the 35-N block is: 70 N pulley Q15 35 N O 1.6 m/s 2 O 3.3 m/s 2 O 4.9 m/s 2 O 6.5 m/52 0 9.8 m/s2