Final answer:
A plane traveling in horizontal flight at 90 m/s has a horizontal velocity of 90 m/s in the direction of its motion. Various physics problems, including projectile motion, airplane speed, and momentum, can be solved using principles of kinematics and vector addition.
Step-by-step explanation:
The question pertains to a plane's velocity in horizontal flight, specific to physics involving motion and kinematics. When a plane is in horizontal flight traveling at 90 m/s, its velocity with respect to the horizontal motion is 90 m/s in the direction of flight. Velocity in physics is a vector quantity, which means it has both magnitude and direction.
Concerning the provided information:
- Projectile motion (part a) can be analyzed by adding the initial horizontal velocity of the plane to the velocity of the projectile relative to the plane, then applying kinematic equations to find the range of the projectile.
- Airplane speed relative to the ground and air mass (part b) can be determined using vector addition, considering the wind's effect on the plane's flight path.
- The concept of momentum, especially angular momentum with regard to a moving airplane (part c), can be evaluated by considering the plane's mass, velocity, and distance from the observer.
These problems involve understanding how velocities combine and how motion is observed differently from various reference frames, which is central to the study of kinematics in physics.