Physics Notes PDF

Work: product of force and distance through which the force acrs and in parallel to the motion. Units for Work -MKS: Joule(J) or Nm -it is the work done by a force of 1N through a distance of 1m -cgs:Erg or D-cm -it is the work done by a force of 1 D through a distance of 1 cm 1 J=10^7 Ergs -...

Work: product of force and distance through which the force acrs and in parallel to the motion. Units for Work -MKS: Joule(J) or Nm -it is the work done by a force of 1N through a distance of 1m -cgs:Erg or D-cm -it is the work done by a force of 1 D through a distance of 1 cm 1 J=10^7 Ergs -fps: -lb-ft-the work done by a force of 1lb through a distance of 1ft. Cases of problems on Work 1.​ Force applied is horizontal W=fd w-: when the force is in the same direction of motion w+: when the force is agoinst the direction of motion 2.​ Force applied is at an angle W=Fxd: Fx=FcosAngle 3.​ Force applied is vertical W=wh w=mg W=mgh  4.​ if there is frictional Force W=F fd 5.​ Work done by varying forces W=1/2 Fe: e-elongation of the spring Hookes law: States that the strain of the material is proportional to the applied stress within the elastic limit of that material. exf: F1e2=F2e1 Power: rate of doing work P=Work done/time but work+forcexdistance Units for power 1.​ watt-J/s or Nm/s 2.​ Horsepower (Hp) - 1Hp= 746watts -1Hp= 550 lbft/s -1Hp= 33,000lb ft/min Energy: Ability to do work -something that an object also acquires which enables it to do work Kinds of Energy: 1.​ Kinetic Energy: due to motion KE=1/2mv^2  3.​ Potential Energy: Due to position, condition or chemical composition Kinds of Potential Energy: 1. Gravitational PE: it is an energy possessed by an object when it is raised to a certain hight GPE=mgh or GPE=wh 2.​ Elastic Potential Energy: possessed by elastic object EPE=1/2k x^2 3.​ Chemical Potential Energy: due to the chemical composition forms of Energy -Mechanical -Chemical -thermal -Light -Sound -Electrical -Nuclear Renewable sources of energy: biomass, geothermal, sunlight (solar), water (tides), and wind Non-renewable sources of energy: fossil fuel (thermal)– coal, crude oil, natural gas nuclear fuel - uranium Conventional sources of energy; thermal, geothermal, hydropower Non-conventional sources of energyn; uclear, tides, biomass, wind, solar Work – Energy Principle (General Form)The total work done is equal to the total change in kinetic and potential energies : Wnet = ∆KE + ∆PE Work – Energy Principle (General Form)The total work done is equal to the total change in kinetic and potential energies: Wnet = ∆KE + ∆PE