Physics 2A Continued

Physics 2A Continued

1. Work and Potential Energy

   • When a force moved on and object through a distance, energy in transferred and work is done
   • Work done= Force x Distance
   • Gravitational Potential Energy is energy due to height
   • Gravitational Potential Energy = Mass x Gravitational Field x Height

2. Kinetic Energy

   • Kinetic Energy is energy of movement
   • Kinetic Energy = 1/5 x Mass x Speed
   • Kinetic Energy transferred is work done
   • 1/2mv = F x d
   • Falling objects convert Ep into Ek

3. Forces and Elasticity

   • Work done to an Elastic object is stored as Elastic Potential Energy
   • Extension of an Elastic object is Directly Proportional to Force
   • Force = Spring Constant x Extention
   • But it stops working when the force is too great
   • There is a maximum force that the Elastic object can take and still extend proportionally

4. Power

   • Power is the 'Rate of doing work' - i.e How much per second
   • Power = Work done / Time Taken
   • Power is measured in Watts (J/s)
   • Calculating the power output is either the amount of Kinetic Energy gained or the amount of Potential Energy gained

5. Momentum and Collisions

   • Momentum = Mass x Velocity
   • Momentum is the property of moving objects
   • The greater the Mass of an object and the greater the Velocity, the more Momentum the object has
   • Momentum before = Momentum after
   • Forces cause changes in Momentum
   • A larger force means a faster change of momentum (so a greater acceleration)

6. Static Electricity

   • The build up of Static is caused by Friction
   • Only Electrons move, the negative charges never move
   • Like charges repel, opposite charges attract
   • Charges can move easily through Conductors

7. Current and Potential Difference

   • 1) Current- Rate of flow of electrons in a circuit
   • 2) Potential Difference- The driving force that pushes around the current
   • 3) Resistance- Slows down something in a circuit
   • Total charge through a circuit depends on Current and Time
   • Current = Charge / Time
   • Potential Difference is the Work Done per unit charge
   • P.D = Work Done / Charge

8. Resistance

   • Resistance increases with Temperature
   • P.D = Current x Resistance

9. Series Circuits

   • 1) Potential Difference is shared
   • 2) Current is the same everywhere
   • 3) Resistance adds up
   • 4) Cell Voltages add up
   • Ammeters are connected in series

10. Parallel Circuits

    • 1) P.D is the same across all components
    • 2) Current is shared between branches
    • Voltmeters are connected in parallel