Free Fall Model: Model Development, Motion, & Force

Sections 4.1 to 4.3

Who dropped a heavy and light object off the Leaning Tower?

Galileo

In the Free Fall model, what are we neglecting?

We are neglecting the effects of air resistance

What are the assumptions for the Free Fall Model?

Particle, 1D motion, Constant Downward Acceleration, Neglect Air Resistance

What is the acceleration near Earth’s surface in the absence of air-resistance called?

Free fall acceleration or acceleration due to gravity

Near Earth’s surface <10 km:

The acceleration due to gravity is approximately constant

Magnitude → 9.80 m/s²

In experiments only, what is the international gravity formula?

(9.979798 ± 0.00003)

Constant:

Always downward → always the same magnitude

Falling object → downward velocity → increasing speed

Acceleration → same direction → downward

Rising object → upward velocity → speed decreasing

Acceleration→ opposite direction → downward

Object momentarily at rest after rising and before falling:

Does NOT remain at rest → begins to fall

Acceleration → downward

What units are acceleration given in?

Units of g

A jet pilot experiences an acceleration of 35 m/s². What is this acceleration in terms of g?

3.6 g

The Free Fall model has what?

A constant, downward acceleration

We change to the symbol y for vertical problems

Each motion with constant acceleration must have:

Two unknowns, solvable with the appropriate two equation

A 15g ball is dropped from rest and from a height of 1.5 m. Determine the unknowns just before it strikes the floor. What are the unknowns for this problem?

Final time

Final velocity

Assuming +y upward, what is the acceleration of an object that is falling near Earths surface in the absence of air resistance?

a_y = -9.80 m/s²