positive half trajectory

例句：

1. 1.The satellite's trajectory is determined bythe sun's position and the earth's rotation.
   卫星的轨迹由太阳的位置和地球的旋转决定。
2. 2. The spacecraft's trajectory was carefully planned to avoidcollision with other spacecraft.
   宇宙飞船的轨迹被仔细规划，以避免与其他宇宙飞船相撞。
3. 3. The trajectory of the projectileis influenced by gravity and air resistance.
   弹丸的轨迹受到重力和空气阻力的影响。