This short video was created to demystify the process of the center-seeking centripetal force and how it acts to keep objects moving along a curved path. The video uses footage of a looping roller coaster and a high school student swinging a cup of water around his head without spilling. It's a well-balanced, engaging explanation of what makes a roller coaster rider feel pinned to the seat -- it's not just the seat belt, it's centripetal force pushing the cars downward toward the center of the loop. Resource includes background information and discussion questions.
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Editor's Note:Why we like it -- this video does a remarkably good job of explaining why you feel a sensation of being thrown outward from the center during circular motion, although there is no outward net force. It will help students differentiate centripetal force from the fictitious "centrifugal force". See Related Materials for a video from the International Space Station that demonstrates centripetal force in a weightless environment.
Metadata instance created
November 19, 2012
by Caroline Hall
February 20, 2014
by Caroline Hall
AAAS Benchmark Alignments (2008 Version)
4. The Physical Setting
4B. The Earth
6-8: 4B/M3. Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force.
3-5: 4F/E1bc. The greater the force is, the greater the change in motion will be. The more massive an object is, the less effect a given force will have.
6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.
6-8: 4F/M3b. If a force acts towards a single center, the object's path may curve into an orbit around the center.
9-12: 4F/H1. The change in motion (direction or speed) of an object is proportional to the applied force and inversely proportional to the mass.
9-12: 4F/H2. All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion.
Next Generation Science Standards
Disciplinary Core Ideas (K-12)
Forces and Motion (PS2.A)
Each force acts on one particular object and has both strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object's speed or direction of motion. (Boundary: Qualitative and conceptual, but not quantitative addition of forces are used at this level.) (3)
The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. (6-8)
Newton's second law accurately predicts changes in the motion of macroscopic objects. (9-12)
Crosscutting Concepts (K-12)
Cause and Effect (K-12)
Cause and effect relationships may be used to predict phenomena in natural or designed systems. (6-8)
Systems and System Models (K-12)
A system can be described in terms of its components and their interactions. (3-5)
Structure and Function (K-12)
Structures can be designed to serve particular functions. (6-8)
Interdependence of Science, Engineering, and Technology (K-12)
Knowledge of relevant scientific concepts and research findings is important in engineering. (3-4)
Science is a Human Endeavor (3-12)
Science affects everyday life. (3-4)
This resource is part of a Physics Front Topical Unit.
Topic: Kinematics: The Physics of Motion Unit Title: The Case of Roller Coasters
This short video does a great job of demonstrating centripetal force and how it acts to keep objects moving along a curved path. What makes a rider on a roller coaster feel a sensation of being thrown outward from the center during a loop, although there is no outward net force? The video serves to help beginners understand the dynamics of circular motion.
%0 Electronic Source %D 2008 %T PBS Learning Media: Centripetal Force - Roller Coaster Loops %I WGBH Educational Foundation %V 2014 %N 1 November 2014 %9 application/flash %U http://www.pbslearningmedia.org/resource/phy03.sci.phys.mfw.roller/centripetal-force-roller-coaster-loops/
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