Who Hits the Ground First? - Gravity Explained

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SUMMARY

In the discussion titled "Who Hits the Ground First? - Gravity Explained," it is established that two individuals, regardless of their weights (10 stone and 20 stone), will hit the ground simultaneously when jumping from a height, provided air resistance is negligible. In an airless environment, such as the Moon, both individuals experience the same acceleration due to gravity. On Earth, air resistance affects the fall time, influenced by the shape and profile of the bodies. The relationship between weight and acceleration is explained through Newton's second law and the formula for calculating gravitational force.

PREREQUISITES
  • Understanding of Newton's second law of motion
  • Basic knowledge of gravitational force calculations
  • Familiarity with the concept of air resistance
  • Awareness of the differences between environments with and without atmosphere
NEXT STEPS
  • Research the effects of air resistance on falling objects
  • Study gravitational acceleration on different celestial bodies
  • Explore Newton's laws of motion in greater detail
  • Learn about the mathematical formulas for calculating gravitational force
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This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of gravity and motion, particularly in relation to air resistance and its effects on falling objects.

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If two people - one weighing 10 stone and the other weighing 20 stone - both jump off a building who would hit the ground first?

I know they would land at the same time but why?:confused:
 
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It all depends on the air resistance - if there is any.
If they jumped of a building on the moon, an airless environment, then they would both have the same acceleration and would hit the ground at the same time, regardless of their weights.

On the earth, where there is an atmosphere, then there would be air resistance, which would slow down the fall.

Air resistance would depend upon the profile, or outline shape of the falling bodies, as well as other factors. A grosser body would have a greater profile than a leaner body and so would have a greater amount of air resistance. The more resistance, the longer it would take to fall.
 
If air resistance is negligible (such as for a short jump) the acceleration due to gravity of all things is the same. This comes from comparing two formulas. One is the simple formula for calculating weight (force of gravity) near the Earth's surface. The other formula is Newton's second law. Rearrange this second law formula to solve for acceleration.
 

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