Definition
The time taken for an object to reach the ground from a specific height is determined by the acceleration due to gravity. This concept follows Newton’s second equation of motion, which calculates displacement, initial velocity, acceleration, and time.
Theory
Newton’s equation of motion is:
s = ut + (1/2) * a * t^2
where:
- s is the displacement or height
- u is the initial velocity or starting speed
- a is the acceleration
- t is the time
For an object dropped from height h:
- The initial velocity u is 0, as it starts from rest
- The acceleration a is equal to g, which is the acceleration due to gravity
- The displacement s is equal to h, the height from which the object is dropped
By substituting these values, the equation simplifies to:
h = (1/2) * g * t^2
This gravity-based experiment demonstrates how objects fall under Earth’s gravitational force.
Real-World Applications
This free-fall physics experiment has several practical applications, such as:
- Physics education – Used in STEM learning, high school experiments, and virtual labs like Dencity.
- Skydiving and sports – Helps determine the descent time for parachutists.
- Construction and engineering – Helps estimate fall times for safety tests in skyscraper construction.
- Astronomy and planetary studies – Used to examine how gravity differs on planets like the Moon or Mars.
Observations and Key Learnings
- Increasing the height increases the fall time.
- Decreasing the height reduces the fall time.
- Gravity affects fall time – objects fall slower on the Moon (where g is lower) and faster on Jupiter (where g is higher).
- Air resistance is ignored in this ideal case but can affect real-life falls.
