Understanding the Concepts
* Free Fall: This means the only force acting on the object is gravity. We assume no air resistance.
* Acceleration due to Gravity (g): On Earth, this is approximately 9.8 m/s². This means the velocity of a freely falling object increases by 9.8 meters per second every second.
* Initial Velocity (v₀): Since the object is in free fall, we assume it starts from rest, so v₀ = 0 m/s.
The Formula
We can use the following kinematic equation:
v = v₀ + at
where:
* v = final velocity
* v₀ = initial velocity
* a = acceleration due to gravity (g)
* t = time
Calculation
1. Plug in the values:
v = 0 m/s + (9.8 m/s²) * (7 s)
2. Calculate:
v = 68.6 m/s
Answer: The velocity of the 3-kg mass after 7 seconds of free fall is approximately 68.6 m/s.
