A spacecraft called Deep Space 1, mass 486 kg, uses an “ion-drive” engine which expels 0.13 kg of xenon propellant each day at 30kms^-1. What is the initial increase in speed of the spacecraft
Use conservation of momentum (p=mv).Momentum of Xenon = 0.13 kg × 30000 m s^-1 = 3900 kg m s^-1Momentum of spacecraft = 486 kg × vv=3900kgms^−1 /486kg=8.02ms^−1
