A newer method of spaceship propulsion is called an ion drive. Charged atoms (ions) of some inert gas (usually krypton or xenon) are propelled out the back of the ship, driving the ship forward. Suppose that a mass m of gas is accelerated each second by an amount Δv.

(a) Write an equation for the force exerted on the ions to accelerate them.
(b) How much force is being exerted on the ship?
(c) If the ship started out with a mass me of fuel, for how long could it continuously fire its engines?