BRAINCAKEFurther Mechanics
Revision notes for Further Mechanics in Edexcel Physics (9PH0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Uniform Circular MotionIf an object is rotating at a steady rate, it has uniform circular motion.
- Angular Displacement1 radian is the angle subtended by an arc of length r where r is the radius of the circle.
- Angular SpeedThe angular speed ω is defined as the angular displacement per second. ω = 2π/T = 2πf The unit of angular speed is radians per second.
- Centripetal AccelerationThe velocity of an object moving at constant speed in a circle changes continuously because its direction changes.
- Proof - centripetal accelerationConsider an object travelling with uniform circular motion at speed v moving in a sort time-interval δt along the perimeter of a circle radius r.
- Centripetal ForceApplying Newton's second law F = ma to the centripetal acceleration gives F = mv2/r Since v = r ω , the centripetal force F = mω2r.
- On the RoadA car going round a roundabout experiences a force towards the centre of the roundabout.
- The London EyeAt the bottom of the wheel, the weight acts downwards and the support force acts upwards.
- A Spin DryerA sock going round a spin dryer experiences a centripetal force.
- Momentum as a VectorMomentum is defined as p = mv where m is the mass (kg) and v is the velocity (m s-1).
- Conservation of Momentum in Two DimensionsThe principle of conservation of momentum: in a closed system (one with no external resultant force), the total momentum before an interaction…
- Resolving Momentum in CollisionsMost two-dimensional collision problems are solved by resolving every momentum into two perpendicular components and applying conservation of…
- Kinetic Energy and Momentum - Ek = p2/2mKinetic energy can be written in terms of momentum.
- Elastic and Inelastic CollisionsIn any collision or explosion in a closed system, total momentum is always conserved, and so is total energy.
- Two-Dimensional Collision QuestionsTwo-dimensional collision questions combine everything in this topic.