Propelling My PowerPropelling My Power
My Power lasts infinitely My Power lasts infinitely
Objective:Objective: Apply the conservation of Apply the conservation of
mechanical energy to different mechanical energy to different situations.situations.
Solve problems on kinetic and Solve problems on kinetic and potential energypotential energy
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Potential Energy
M.E.
Kinetic Energy
Potential EnergyPotential Energy
The potential energy (PE) is The potential energy (PE) is attributed to the height (h) if the mass attributed to the height (h) if the mass (m) is constant.(m) is constant.
If h is increase then PE will increase, If h is increase then PE will increase, and when h is decrease PE will and when h is decrease PE will decrease.decrease.
PE = mgh, g=9.8m/sPE = mgh, g=9.8m/s22
Kinetic EnergyKinetic Energy
The kinetic energy (KE) is attributed to the The kinetic energy (KE) is attributed to the motion (speed or velocity) of an object.motion (speed or velocity) of an object.
The formula in finding the KE of an object is The formula in finding the KE of an object is KE=KE=½mv½mv22
V=speed or velocity of an objectV=speed or velocity of an object M=mass of an object M=mass of an object
Sample problem on Potential EnergySample problem on Potential Energy
What is the potential energy of a 5kg ball that What is the potential energy of a 5kg ball that is 6m high from the ground?is 6m high from the ground?
Given: mass(m)=5kg,acceleration due to Given: mass(m)=5kg,acceleration due to gravity(g)=9.8m/sgravity(g)=9.8m/s22, height(h)=6m, height(h)=6m
Solution:Solution: PE=mghPE=mgh =(5kg)(9.8m/s=(5kg)(9.8m/s22)(6m))(6m) =294kg.m=294kg.m22/s/s22 or 294Joules(J,unit of or 294Joules(J,unit of
potential energy)potential energy)K.E.
Sample Problem on Kinetic EnergySample Problem on Kinetic Energy
If a 0.2kg toy cart moves at a speed of 2m/s,calculate its If a 0.2kg toy cart moves at a speed of 2m/s,calculate its kinetic energy.kinetic energy.
Given: m=0.2kgGiven: m=0.2kg v=2m/sv=2m/s Find KE.Find KE. SolutionSolution KEKE=½mv=½mv22
=½(0.2kg)(2m/s)=½(0.2kg)(2m/s)22
=½(0.2kg)(4m=½(0.2kg)(4m22/s/s22)) =0.4Joules=0.4Joules =0.4J=0.4J
ExercisesExercises
Potential EnergyQuiz
Kinetic EnergyQuiz
AssignmentAssignment
References:References:
1.Physics, Vol 1 By: Avenido,et al1.Physics, Vol 1 By: Avenido,et al Science and Technology of today By:Dizon,et Science and Technology of today By:Dizon,et
alal