Learning requires action. Give your students this sense-making activity from The Curriculum Corner.

Visit The Physics Classroom's Flickr Galleries and take a visual overview of 1D Kinematics.

This EJS simulation from Open Source Physics (OSP) will help students understand the many representations of free fall.

Looking for a lab that coordinates with this page? Try the Dune Buggy Challenge Lab from The Laboratory.

1-D Kinematics - Lesson 5 - Free Fall and the Acceleration of Gravity

**v _{f} = g * t**

(dropped from rest)

where g is the acceleration of gravity. The value for g on Earth is 9.8 m/s/s. The above equation can be used to calculate the velocity of the object after any given amount of time when dropped from rest. Example calculations for the velocity of a free-falling object after six and eight seconds are shown below.

**Example Calculations:**

At t = 6 s

v_{f} = (9.8 m/s^{2}) * (6 s) = 58.8 m/s

At t = 8 s

v_{f} = (9.8 m/s^{2}) * (8 s) = 78.4 m/s

The distance that a free-falling object has fallen from a position of rest is also dependent upon the time of fall. This distance can be computed by use of a formula; the distance fallen after a time of t seconds is given by the formula.

**d = 0.5 * g * t ^{2}**

(dropped from rest)

where g is the acceleration of gravity (9.8 m/s/s on Earth). Example calculations for the distance fallen by a free-falling object after one and two seconds are shown below.

**Example Calculations:**

At t = 1 s

d = (0.5) * (9.8 m/s^{2}) * (1 s)^{2} = 4.9 m

At t = 2 s

d = (0.5) * (9.8 m/s^{2}) * (2 s)^{2} = 19.6 m

At t = 5 s

d = (0.5) * (9.8 m/s^{2}) * (5 s)^{2} = 123 m

(rounded from 122.5 m)

The diagram below (not drawn to scale) shows the results of several distance calculations for a free-falling object dropped from a position of rest.

Next Section:

Jump To Next Lesson:

Physics Tutorial » 1-D Kinematics » Lesson 5 - Free Fall and the Acceleration of Gravity » How Fast? and How Far?