AP Physics 1 Crash Course for Spring 2021 ๐ŸŽก

Get unit reviews, practice essays, and live support!

ap physics 1 study guides

๐Ÿงย  Multiple Choice Questions (MCQs)

3.1 Vector Fields

#uniformcircularmotion

#vectorfield

#vectors

#centripetalforce

โฑ๏ธย ย 2 min read

written by

Peter Apps

peter apps

June 8, 2020


Essential Knowledge 2.A.1 โคต๏ธ

A vector field gives, as a function of position (and perhaps time), the value of a physical quantity that is described by a vector.

Key Concept: Vector Field - the assignment of a vector to each point in a portion of space. A vector field can be visualized as a collection of arrows with a given magnitude and direction, each attached to a point in the plane.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-08%20at%202.57.36%20PM.png?alt=media&token=7cb480ff-f20a-4711-9757-8123224c7def

Image courtesy of Open University.

Uniform Circular Motion

As shown in the image above, a vector field can represent circular motion.ย From this vector field depiction, we can go into more depth of the specific components of uniform circular motion.

Key Concept: Uniform Circular Motion - the motion of an object in a circle at a constant speed that is accelerating due to a change in direction. In UCM there are four typical forces you will deal with: Tension, Friction, Gravity, and Normal. These forces are the cause of centripetal force.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-08%20at%202.59.30%20PM.png?alt=media&token=cfc3e333-6fa8-44b8-89d4-efecffa34bd3

Image courtesy of Quizlet.

From this diagram, we can see in uniform circular motion centripetal acceleration is constant and always pointed towards the center, or center-seeking. Similarly, the centripetal force always points towards the center. However, velocity is tangent from the center; therefore, it is not considered in the net force. All forces pointing towards the center of the circle are positive (+) and all forces pointing away from the center of the circle are negative (-). Anything that doesnโ€™t point away from or towards the circleโ€™s center isnโ€™t considered in the net force.

  • Key Concept: Centrifugal - moving or tending to move away from a center.

  • Key Concept: Centripetal - moving or tending to move toward a center.

  • Key Concept: Centripetal Force - a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.

Equation: Fc = mv^2/r, where Fc is Centripetal Force in Newtons, m is mass in kilograms, v is the velocity in m/s, and r is the radius in meters.

A common misconception with centripetal force is that it is a new force when, in actuality, it is the net force inward and should be treated as such. To prove this concept, letโ€™s dive into how the equation for centripetal force is derived: Newtonโ€™s second law gives us the equation F =ma, which can also be adapted for net force. Acceleration in a uniform circular motion is given as a = v^2/r, so Centripetal Force is simply mass x v^2/r or mv^2/r. Remember to not include centripetal force on any free-body diagrams because it is not a force, but rather the net force.

๐ŸŽฅWatch: AP Physics 1 - Unit 3 Streams

continue learning

Slide 1 of 10
Fiveable Logo

2550 north lake drive
suite 2
milwaukee, wi 53211

92% of Fiveable students earned a 3 or higher on their 2020 AP Exams.

*apยฎ and advanced placementยฎ are registered trademarks of the college board, which was not involved in the production of, and does not endorse, this product.

ยฉ fiveable 2020 | all rights reserved.