Daily AgendaMs. DeSalvoDecember 5, 2013

CPS Bell Ringer: 12/5/13Activity: Energy Review1. What is the unit for energy?2. T or F? If an object has kinetic energy then

it has momentum.3. Give the equations for kinetic and

potential energy.4. Give an example when PE = 0

CPS (Period 6,8)December 5, 2013Last Class(See me for missed work)

• Potential, Kinetic, Chemical & Thermal Energy

Today

• Hand in LOL Homework• Energy Formulas• Working the

Problems

Kinetic and Potential Energy

•KE= ½ mv2

• m= mass (kg)• v= velocity (m/s)

• PE= mgh• m= mass (kg)• g= gravity (9.8m/s2)• h= height (m)• Total Energy = KE + PE• (Conservation of energy)

5

Practice Problem #1 Kinetic Energy• A 181 kg motorcycle is traveling at 76 m/s. How much kinetic

energy does it have?

G U E S S

6

Practice Problem #2 Potential Energy• How much gravitational potential energy does a 120 kg person

have on top of a 25 m building?

G U E S S

7

Practice Problem

• A 50-caliber bullet has a mass of 0.045 kg and a KE of 5600 J. • What is the velocity of the bullet?

G U E S S

Conservation of Energy• As the 2.0-kg pendulum bob in the above diagram swings to

and fro, its height and speed change. Use energy equations and the data to determine the blanks in the above diagram.

• A - __________ B - __________ C - __________ D - __________ E - __________ F - __________

Physical Science Practice Wkst• Work with the person next to you!