Final answer:
For an object launched horizontally with a speed of 5 m/s from a height of 3m, the known variables are the horizontal launch speed, the height of launch, acceleration due to gravity, the initial vertical speed, and the time of flight which can be derived.
Step-by-step explanation:
When an object is launched horizontally with a given speed from a certain height, several variables are immediately known, which are essential for analyzing the object's motion. In this scenario where the object is launched at a speed of 5 m/s from a height of 3m, the known variables are:
- The horizontal launch speed (vx) of the object: 5 m/s.
- The height (h) from which the object is launched: 3m.
- Acceleration due to gravity (g): approximately 9.81 m/s2, assuming we're near the Earth's surface.
- Initial vertical speed (vy): 0 m/s, since the object is launched horizontally.
- The time of flight, which can be calculated using the height and acceleration due to gravity.