Vertical Circles
Part of the Mechanics section of Coddy's Physics journey. Lesson 75 of 94.
In a vertical circle the weight always points down. With the direction toward the centre positive:
top: T + mg = mv²/r, bottom: T - mg = mv²/r
At the top both forces point to the centre; at the bottom the weight points away from it.
The string pulls hardest at the bottom. On a roller coaster the seat's normal force N plays the part of T: at the bottom of a dip the rider feels heavier.
Challenge
A 60 kg rider on a roller coaster passes through the bottom of a dip. There her acceleration is 5 m/s², straight up toward the centre of the dip. Find the normal force N from her seat.
Try it yourself
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Mechanics
1Vectors and Newton's Laws
Right TrianglesWhat is a Vector?Adding VectorsAxes and DirectionsVector ComponentsForces Around UsFriction and TensionNewton's First LawNewton's Second LawNewton's Third LawRecap - Net Force2Friction
What is Friction?Static FrictionKinetic FrictionFriction and Newton's LawsRecap - Sliding Crate14Circular Motion
Uniform Circular MotionCentripetal AccelerationHorizontal CirclesVertical CirclesLoop the LoopRecap - Car on a Curve3Inclined Planes
Forces on an InclineGravity ComponentsFrictionless InclineIncline with FrictionWill It Slide?Recap - Ramp Challenge6Projectile Motion
Independent AxesHorizontal LaunchLaunch at an AngleRange and Max HeightRecap - Hit the Target9Work and Energy
WorkKinetic EnergyWork-Energy TheoremGravitational PEConservation of EnergyPowerRecap - Roller Coaster12Impulse and Momentum
MomentumImpulseConservation of MomentumElastic CollisionsInelastic CollisionsRecap - Air Track15Simple Harmonic Motion
What is SHM?Mass on a SpringThe PendulumSHM GraphsEnergy in SHMRecap - Oscillator