Correct Answer : Ballistic trajectory
Explanation : A ballistic missile trajectory is used by missiles for warfare purposes. It is different from the orbit followed by the satellite as the ballistic missile trajectory intersects the Earth’s surface. The trajectory comprises of three portions-powered flight regime, free flight regime and the re-entry regime.
Correct Answer : It intersects the earth’s surface
Explanation : The trajectory of a missile differs from a satellite orbit in only one respect-it intersects the surface of the Earth at two places. If we consider only the free-flight portion of the ballistic missile trajectory, then it follows the conic orbit just like a satellite.
Correct Answer : Cruise portion
Explanation : The ballistic trajectory is composed of three components-powered flight portion which is comprises of path from launch to the burnout, free-flight portion which constituted most of the trajectory and the re-entry portion which lasts until the impact.
Correct Answer : 2
Explanation : The value of non-dimensional parameter varies from point to point in an orbit. The value of the parameter for a satellite that has an escape speed and is on the path of the parabolic path is 2. Q=1 is the condition for circular orbit.
Correct Answer : High trajectory
Correct Answer : Low trajectory
Explanation : Flight path for a trajectory yields two solutions. The solution having the smaller value is known as the low trajectory and the solution with higher value is known as the high trajectory. The nature of high or low trajectory is dependent on the value of Qbo.
Correct Answer : Rotation of the earth is ignored
Explanation : In order to derive the ballistic missile trajectory equations, there are two assumptions made. First is that the rotation of the earth is ignored and second is that the free-flight trajectory is assumed to be symmetrical.
Correct Answer : Elliptical
Explanation : Ballistic missile trajectory is composed of three regimes-powered flight, free-flight and re-entry portion. Free-flight portion is the only part of the trajectory that follows a conic orbit. It constitutes most of the trajectory path. During free-flight the trajectory is part of a conic orbit-almost always an ellipse which is symmetrical.
Correct Answer : Hyperbolic
Correct Answer : Angle between the local horizontal and the tangent
Correct Answer : 1
Explanation : On plotting free flight range vs flight path angle graph, we get a curve as shown in the figure. The flight path angle first increases then decreases within the range of 0-90 degrees. On reaching the maximum point, there’ only one corresponding flight path angle. For rest of the range values, there are two corresponding flight path angles. Thus, there’s is only one path to the target.
Correct Answer : 81.52 degrees
Explanation : There’s error produced when there’s variation in the speed, launch direction, position of the ballistic missile. They are classified into two errors-down-range errors, out-of-plane errors.
Correct Answer : Effect of a Lateral Displacement of the Burnout Point
Explanation : Only the effect of lateral displacement at the burnout among the options results in the missile to hit to right or left of the target i.e., it is a out-of-plane error. Rest of them are down-rage errors and the error in the intended plane causes either a long or a short hit.
Correct Answer : 5 nm
Explanation : An error in down-range position at thrust cutoff produces an equal error at impact. If the actual burnout point is 5 nm farther down-range than was intended, the missile will overshoot the target by exactly 5 nm.
Correct Answer : Missile overshoots the target
Explanation : If the burnout occurs higher than intended, the missile overshoots and if burnout occurs too low, the missile falls short of the target in every case.
Correct Answer : Missile falls short of the target
Explanation : Speed at burnout affects range as causing down-range error. If the missile is too fast at the burnout, it overshoots and if it is too slow, the missile falls short.
Correct Answer : 1524 ft/s
Explanation : The Earth rotates once on its axis in 23 hours 56 min producing a surface velocity at the equator of 1524 ft/sec. The rotation is from west to east.
Correct Answer : Subtracting the initial eastward velocity of launch site
Explanation : The compensation for the initial velocity is done by recognizing that the true velocity of the missile at burnout is the velocity relative to the launch site (which could be measured by radar) plus the initial eastward velocity of the launch site due to earth rotation.
