Gravity plays a crucial role in our everyday lives, affecting everything from our to how objects fall. Understanding the relationship between and is key to grasping the concept of gravity and its effects on Earth and beyond.
Air resistance and weightlessness are fascinating aspects of gravity's influence. These concepts explain why skydivers reach and why astronauts float in space, showcasing the complex interplay between gravity and other forces in different environments.
Mass, Weight, and Gravity
Mass vs weight relationship
Mass represents the intrinsic property of an object, measuring the amount of matter it contains (atoms, molecules)
Remains constant regardless of location (Earth, Moon, space)
Measured in kilograms (kg) or slugs (imperial units)
Determines an object's , or resistance to changes in motion
Weight is an extrinsic property, the exerted on an object due to gravity
Varies depending on the strength of the gravitational field (Earth vs Moon)
Measured in newtons (N) or pounds (lbs)
Weight is directly proportional to mass, related by the equation [w = mg](https://www.fiveableKeyTerm:w_=_mg)
w represents weight, m represents mass, [g](https://www.fiveableKeyTerm:g) represents
On Earth's surface, g is approximately 9.8 m/s2 or 32 ft/s2
Examples
A person with a mass of 70 kg weighs about 686 N on Earth
The same person would weigh about 114 N on the Moon, where g≈1.62 m/s2
Air resistance effects on falling
motion occurs when an object is under the influence of gravity alone
Acceleration is constant and equal to the (g)
Neglects air resistance for simplicity
Air resistance is a force acting opposite to the direction of motion
Increases with the object's velocity and surface area (parachute vs bullet)
Causes objects to reach a when air resistance equals the force of gravity
Air resistance reduces the acceleration of falling objects
Objects with different masses but similar surface areas fall at similar rates (paper vs coin)
Explains why a feather and a bowling ball fall at different rates in air but at the same rate in a vacuum
Examples
A skydiver reaches a terminal velocity of about 55 m/s (120 mph) due to air resistance
A penny and a feather dropped from the same height in a vacuum will hit the ground simultaneously
Conditions for weightlessness
Weightlessness occurs when an object appears to have no weight
The only force acting on the object is gravity
Conditions that create weightlessness
: Objects experience apparent weightlessness (skydiving, amusement park rides)
Orbit: Spacecraft and astronauts experience continuous free fall around a celestial body (ISS)