FREE-FALL

Chapter 2

FLASH-BACK

Always work!

ONLY WHEN A = CONST

Free FallAcceleration due to gravitation

Galileo Galilei (1564 – 1642)

In a system with no air resistance

all objects fall with equal acceleration

In the absence of air resistance, it is found that all bodiesat the same location above the Earth fall vertically with the same acceleration. If the distance of the fall is smallcompared to the radius of the Earth, then the accelerationremains essentially constant throughout the descent.

This idealized motion is called free-fall and the accelerationof a freely falling body is called the acceleration due to gravity.

22 sft2.32or sm80.9g

Galileo mathematically proved that distance traveled by an object falling down from rest is proportional to the square of the time period elapsed:

Example 10 A Falling Stone

A stone is dropped from the top of a tall building. After 3.00sof free fall, what is the displacement y of the stone?

Example How High Does it Go?

The referee tosses the coin up with an initial speed of 5.00m/s. In the absence if air resistance, how high does the coin go above its point of release?

GIVEN UNITS EQUATIONS SUBSTITUTE / SOLVE

Example How long is the coin in the air?

The referee tosses the coin up with an initial speed of 5.00m/s. In the absence if air resistance, how long will it take for the coin to fall back down and what speed will it have when it comes back?

GIVEN UNITS EQUATIONS SUBSTITUTE / SOLVE

Example How long is the coin in the air?

The referee tosses the coin up with an initial speed of 5.00m/s. In the absence if air resistance, how high above the hand will the coin rise before falling back down?

GIVEN UNITS EQUATIONS SUBSTITUTE / SOLVE