Answer:
197.2 s
Explanation:
First of all, let's convert the mass of the ocean liner into kilograms:
[tex]m=40,000 Mg = 40,000,000 kg = 4\cdot 10^7 kg[/tex]
and the initial velocity into m/s:
[tex]u=4 km/h =1.11 m/s[/tex]
The force applied is
[tex]F=-225 kN = -2.25\cdot 10^5 N[/tex]
So we can find first the deceleration of the liner:
[tex]a=\frac{F}{m}=\frac{-2.25\cdot 10^5 N}{4\cdot 10^7 kg}=-5.63\cdot 10^{-3} m/s^2[/tex]
And now we can use the following equation:
[tex]a=\frac{v-u}{t}[/tex]
with v = 0 being the final velocity, to find t, the time it takes to bring the liner to rest:
[tex]t=\frac{v-u}{a}=\frac{0-1.11 m/s}{-5.63\cdot 10^{-3} m/s^2}=197.2 s[/tex]
