Instructional Video
Sophia Learning

Sophia: Gravitational Force & Newton's Second Law

For Students 9th - 10th
This lesson explains how gravitational force is related to free fall, acceleration due to gravity, and Newton's second law of motion.
Instructional Video
Khan Academy

Khan Academy: Would a Brick or Feather Fall Faster?

For Students 9th - 10th
What would fall faster on the moon, a brick, or a feather? Sal Khan answers this question in this video. [10:34]
Instructional Video
Khan Academy

Khan Academy: Normal Force: Normal Force and Contact Force

For Students 9th - 10th
A discussion of the force that keeps a block of ice from falling towards the center of the Earth. The example problem has two 5-kg blocks of ice on the surface of a frozen lake, one stationary and one moving at a constant velocity. [7:18]
Instructional Video
Khan Academy

Khan Academy: Mass and Weight Clarification

For Students 9th - 10th
Sal Khan explains the difference between mass and weight. [10:40]
Instructional Video
PBS

Wnet: Thirteen: Circus Physics: Projectile Motion

For Students 9th - 10th
Jugglers know that if you throw an object into the air, it will follow a curved path -- as the ball moves horizontally, gravity pulls it down vertically. Physicists call this projectile motion. In this video, you will learn why...
Instructional Video
Khan Academy

Khan Academy: Mass Swinging in a Horizontal Circle

For Students 9th - 10th
In this video, David from Khan Academy explains how to solve for the tension and speed of a mass swinging at an angle in a horizontal circle. [12:38]
Instructional Video
Khan Academy

Khan Academy: Centripetal Force and Acceleration Intuition

For Students 9th - 10th
This video shows the direction of the force in cases of circular motion at constant speeds. Several examples of centripetal force in everyday life are given. [10:46]