Understanding the Concepts
* Free Fall: In a vacuum, an object falls freely under the influence of gravity alone. No air resistance affects its motion.
* Acceleration due to Gravity (g): On Earth, the acceleration due to gravity is approximately 9.8 m/s². This means an object's velocity increases by 9.8 meters per second every second it falls.
* Initial Velocity: Since the object is dropped, its initial velocity (v₀) is 0 m/s.
The Formula
We can use the following equation from kinematics:
* v = v₀ + at
Where:
* v = final velocity (instantaneous speed)
* v₀ = initial velocity
* a = acceleration due to gravity (g = 9.8 m/s²)
* t = time
Calculation
1. Plug in the values:
* v = 0 + (9.8 m/s²)(2 s)
2. Solve for v:
* v = 19.6 m/s
Answer: The instantaneous speed of the object 2 seconds after being dropped in a vacuum is 19.6 m/s.
