Answer:
N₁ = 222 N , N₂ = 1035 N , N₃ = 148735 N
Explanation:
See the attachment for parts a and b
c) Let's use Newton's second law for each body, let's start with the child
N₁- W_child = m₁ a
N₁ = m₁ a + W_child
N₁ = m₁ (a + g)
Where m₁ is the child's masses
N₁ = 15 (5 + 9.8)
N₁ = 222 N
For the woman
N₂ –W_child - W-woman = m₂ a
Where m₂ is the woman's mass
N₂ = m₂ a + m₂ g + m₁ g
N₂ = 60 5 + 9.8 (60 +15)
N₂ = 1035 N
For the plane
N₃ - W_child - W_woman - W_plane = m₃ a
Where m₃ is the mass of the plane
N₃ = m₃ a + g (m₁ + m₂ + m₃)
N₃ = 10000 5 + 9.8 (15 + 60 + 10000)
N₃ = 148735 N
d) when the plane accelerates down the two accelerations are in the same direction, which is why, when the plane accelerates upwards the two accelerations and are subtracted, this is the force that the plane exerts on the child. The feeling of weight that is the force that the child applies against the plane is higher when it accelerates upwards.