First, let's calculate the initial and final speed of the spaceship:
[tex]v_i = 3500 km/h = 972.2 m/s[/tex]
[tex]v_f = 1700 km/h = 472.2 m/s[/tex]
By using the initial and final speed, we can calculate the acceleration of the spaceship:
[tex]a= \frac{v_f-v_i}{t}= \frac{472.2 m/s-972.2 m/s}{1 s}= -500 m/s^2 [/tex]
where the negative sign means it is directed against the motion of the spaceship (in fact, the spaceship is decelerating).
And now, by using Newton's second law:
[tex]F=ma[/tex]
we can calculate the net force that acted on the spaceship:
[tex]F=(10000 kg)(-500 m/s^2)=-5 \cdot 10^6 N[/tex]
where the negative sign means it is directed against the direction of motion of the spaceship.
