The propulsive force generated by a rocket motor as a result of the ejection of exhaust gases. Under ideal (vacuum) conditions, thrust is equal to the product of the mass ejected per unit time multiplied by the EXHAUST VELOCITY of the ejected matter; it is expressed in units of kilogrammes (kg) weight (1 kg weight is the fore experienced by a mass of 1 kg on the Earth's surface due to the gravitational attraction of the earth). Alternatively, thrust may be expressed in terms of force, the newton being the SI unit of force.
If a rocket is to lift off the ground it must generate a thrust greater than its own weight.
