Have you ever wondered how fast a person falls when they jump from a height? It seems like a simple question with a straightforward answer. However, the reality is more complicated than you might think. In this article, we will explore the science behind falling and answer some of the most common questions related to this topic.
Gravity and Falling
Gravity is the force that pulls objects towards each other. The strength of the gravitational force depends on the mass of the objects and the distance between them. When a person jumps from a height, the force of gravity pulls them towards the Earth. The acceleration due to gravity is approximately 9.81 meters per second squared (m/s2) near the Earth’s surface. This means that a person falls faster and faster every second they are in freefall.
Terminal Velocity
As an object falls, it reaches a point where it can’t fall any faster due to the air resistance. This point is called terminal velocity. Terminal velocity is different for every object and depends on its shape, size, and weight. For a human body, the terminal velocity is around 53 meters per second or 120 miles per hour.
Factors that Affect Falling Speed
Several factors affect how fast a person falls, including:
- Body position
- Air resistance
- Altitude
- Weight
- Surface area
Body position is one of the most significant factors that affect falling speed. A person falls faster in a head-down position than in a spread-eagle position. This is because the air resistance is lower in the head-down position. Similarly, a person with a smaller surface area falls faster than a person with a larger surface area.
Freefall Time
Freefall time is the time it takes for a person to fall from a particular height to the ground. It depends on the height and the initial velocity of the person.
Calculating Freefall Time
The formula to calculate freefall time is:
t = √(2 × h ÷ g)
where
- t = time (in seconds)
- h = height (in meters)
- g = acceleration due to gravity = 9.81 m/s2
For example, if a person jumps from a building that is 80 meters high, the freefall time would be:
t = √(2 × 80 meters ÷ 9.81 m/s2) = 4.04 seconds
Surviving a Fall
Falling from a height can be deadly. However, there have been cases where people have survived falls from incredible heights. The chances of survival depend on various factors, including the height of the fall, the landing surface, and the body position.
Famous Survivors
There have been several famous cases of people surviving falls from great heights:
| Person | Height | Landing Surface | Outcome |
|---|---|---|---|
| Alan Magee | 20,000 feet | Roof of a train station | Survived with multiple injuries |
| Felix Baumgartner | 128,100 feet | Parachute landing | Survived with no injuries |
| Vesna Vulović | 33,000 feet | Mountain slope covered in snow | Survived with multiple injuries |
Conclusion
Now you know that falling is not as simple as it may seem. Several factors affect how fast a person falls, including body position, air resistance, altitude, weight, and surface area. Terminal velocity is the fastest speed that a person can reach while falling due to air resistance. Freefall time depends on the height and initial velocity of the person. Finally, surviving a fall is possible, but the chances of survival depend on various factors.
References
- Butkov, E. (2017). Physics for Scientists and Engineers. Cengage Learning.
- Park, R. R. (2018). The fall. Skyhorse Publishing Inc.
- Ward-Smith, A. J. (2013). Falling bodies: physics and pathology. New York, NY: Springer.
Common Questions and Their Answers
- Q: How fast does a person fall?
- Q: What factors affect how fast a person falls?
- Q: How do you calculate freefall time?
- Q: Can people survive falls from great heights?
A: The terminal velocity of a human body is around 53 meters per second or 120 miles per hour.
A: Body position, air resistance, altitude, weight, and surface area are some of the factors that affect how fast a person falls.
A: Freefall time can be calculated using the formula: t = √(2 × h ÷ g), where t is the time in seconds, h is the height in meters, and g is the acceleration due to gravity which is approximately 9.81 m/s2.
A: Although falling from a height can be deadly, there have been cases of people surviving falls from great heights. The chances of survival depend on various factors.