Does gravity act upon all objects equally, or do the properties (like mass, shape) of the objects come into play?
Concept: Gravity is an attractive force and depends upon the mass of objects. The acceleration due to gravity is constant for all falling objects. Mass affects size/amount of gravity but all objects accelerate at the same rate due to gravity.
Guiding Question: How does gravity pull on all masses and what affects does it have on the masses?
Although gravity accelerates all objects at the same rate near the Earth’s surface (9.8m/s2), the force due to gravity does not pull on all objects equally. The mass of the objects and the distance between objects determine the force. The factors of air resistance and surface area will also affect the rate an object falls toward Earth when not in a vacuum.
Notes / Reading RESOURCEs
Simulations / LABS
GoMotion Lab: Falling Tray
The graph below is for the distance the tray travels over the amount of time it takes to hit the floor.
Forces on a Skydiver
Feather and Ball
Forces in Action - Speed of a Skydiver
Misconceptions About Falling Objects
gravity - A force of attraction between objects that is due to their masses.
air resistance - the fluid friction experienced by objects falling through the air; frictional force air exerts on a moving object; acts opposite in direction to the object's motion
vacuum - an empty space with no air
velocity - speed in a given direction
terminal velocity - constant velocity of a falling object when the force of air resistance equals the force of gravity
free fall - the motion of a falling object when the only force acting on it is gravity (no air resistance)
universal law of gravitation (gravity) - every object in the universe is attracted to every other object by gravity; the force of gravity acts between all objects in the universe
acceleration - the rate at which velocity changes