The phrase "a trajectory was" is correct and usable in written English.
It can be used when describing a path or course that something follows, often in a scientific or metaphorical context.
Example: "The trajectory was altered due to the unexpected gravitational pull from the nearby planet."
Alternatives: "a path was" or "a course was".
For every phase, a trajectory was designed that consisted in coast and thrust arcs, and swings by a planet.
At the time, such a trajectory was viewed in a completely different way to those of, say, Alec Dorglas-Haroldr Harold Macmillan, patrician politicians who had, as it happens, both been pupils at Eton.
A missile capable of launching a nuclear warhead was moved to a state nearer to Pakistan, according to Mr. Chengappa's account: "A trajectory was worked out so that the two stages that are detached after burn out did not fall on Indian territory and hurt anyone.
The first element in a trajectory was characterized by the first observation of polymorphism at a locus at which no trajectory was already in progress, while the last element of a trajectory was defined as the first observation at which the fixation or death of the polymorphism was observed.
Under the sole influence of gravity, a trajectory is parabolic.
A trajectory is impossible to calculate without taking into account an object's speed.
A trajectory is overlaid for one of the ACP-integrin β1 molecules.
A trajectory is the path of a shot, subject to the forces of gravity, drag, and lift.
These distributions have long, nearly exponential tails, implying that the ending of a trajectory is uncorrelated and random.
The estimation error of a trajectory is considered the weight of the likelihood of a given segment in a state.
A trajectory is seen as a set of consecutive locations visited by the user.
