A10,000 kg spaceship decelerates uniformly to reduce its speed from 3,500 km/h to 1,700 km/hr in 1 s. what net force acted on this spaceship

First, let's calculate the initial and final speed of the spaceship:



By using the initial and final speed, we can calculate the acceleration of the spaceship:

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:

we can calculate the net force that acted on the spaceship:

where the negative sign means it is directed against the direction of motion of the spaceship.

If football was tossed in air without gravity or friction the ball would go into space