Given data
*The space probe with a mass is 4000 kg
*The expels mass from the space probe is M = 3500 kg
*The expels mass moving with the velocity is v = 2000 m/s
*The remaining mass is m = 500 kg
The expression for the velocity of the remaining 500 kg of the probe is given by the conservation of momentum as
Substitute the values in the above expression as