Final answer:
The information provided allows us to infer certain key aspects of the projectile's journey, such as the initial velocity, maximum height, and time of flight. Projectile motion is symmetric, and the initial velocity can be determined through the final velocity just before hitting the ground.
Step-by-step explanation:
The question provided examines various aspects of projectile motion, analyzing the time of flight, maximum height, velocities at different points, and the height of the projectile after a certain amount of time. From the information given, we can infer several things about this projectile's motion. First, the upward journey to the maximum height takes 2 seconds, while the entire journey takes 4 seconds; this indicates that the downward journey also takes 2 seconds, as expected due to symmetry in projectile motion in the absence of air resistance.
The maximum height reached is 20 meters, and since the initial velocity at the point of return to the initial height is -20 m/s, the positive initial velocity must have been 20 m/s (considering the acceleration due to gravity as -9.8 m/s²). Furthermore, the velocity just before hitting the ground is -40 m/s, suggesting the projectile accelerated due to gravity during the fall after being launched. The height of 5 meters after 5 seconds is indicative of the projectile being on its downward trajectory, having passed the maximum height already.
Given that the formulas for projectile motion show that time of flight depends only on the vertical component of motion, any projectile with a given initial vertical speed and landing altitude variance will display a predictable time of flight. Thus, by knowing the initial vertical velocity or the change in height, we can calculate the time of flight and other kinematic variables of the motion.