Answer
given,
time = 10 s
ship's speed = 5 Km/h
F = m a
a is the acceleration and m is mass.
In the first case
F₁=m x a₁
where a₁ = difference in velocity / time
F₁ is constant acceleration is also a constant.
Δv₁ = 5 x 0.278
Δv₁ = 1.39 m/s

a₁ = 0.139 m/s²
F₂ =m x a₂
F₃ = F₂ + F₁
Δv₃ = 19 x 0.278
Δv₃ = 5.282 m/s
a₃=Δv₂ / t

a₃ = 0.5282 m²/s
m a₃=m a₁ + m a₂
a₃ = a₂ + a₁
0.5282 = a₂ + 0.139
a₂=0.3892 m²/s
F₂ = m x 0.3892...........(1)
F₁ = m x 0.139...............(2)
F₂/F₁
ratio = 
ratio = 2.8
When the roller coaster going down
step by step
Given that.
F=3•i+4•j
And it from point (0,0)m to (5,6)m
dx=final position - initial position
dx=(5,6)-(0,0)
dx=(5,6)m
dx=5•i +6•j
Work done by the force is give by
W = F•dx
W=F•dx
Note that i•i=j•j=1 and i•j=j•i=0
Then,
W=(3i+4j)•(5i+6j)
Therefore,
W=3i•(5i+6j)+4j•(5i+6j)
W=15i•i+18i•j+20j•i+24j•j
W=15+0+0+24
W=39J
Then the work done by the force is 39 Joules
Answer : The products of this reaction are,
and 
Explanation :
First we have to write the balanced chemical reaction.

In this reaction, 1 mole of copper nitrate react with the 2 moles of sodium hydroxide to give 1 mole of copper hydroxide and 2 moles of sodium nitrate.
This reaction is a double displacement reaction.
Double displacement reaction : A type of reaction in which a positive cation and a negative anion of two reactants react to exchange their places to form two new products.
The general representation of this reaction is,
(X and A are the cations, Y and B are the anions)
Hence, the products of this reaction are, copper hydroxide,
and sodium nitrate,