Policastro/Finizio
Contemporary Physical Science
Period 4
Quiz Date: 1/12/05
Pendulum Problems, Work Problems, and Section 15.1
Study Guide
Formulas
1. Potential Energy =
*Remember Gravity always equals 9.8
*Unit for Potential Energy is Joules
2. Kinetic Energy =
*unit for Kinetic Energy is the Joule
3. Force =
*unit for Force is the Newton
4. Work =
*unit for work is the Joule
Section I: Kinetic/Potential Energy Problems
Sample Problem #1
Calculate the kinetic energy of a 1kg toy car traveling at a constant velocity of 2 m/s.
*In order to calculate the Kinetic Energy, you must plug your numbers into the formula.
Mass = 1kg
Velocity = 2 m/s
Kinetic Energy = 1 Joule
Sample Problem #2
Find the Velocity of a Pendulum using the given data.
Mass: 3 Kg
Height: 1 meter
Potential Energy =
Potential Energy = 29.4 Joules
Section II. Work Problems
What is the work done by a weight lifter who lifts a 1600-newton barbell over his head? Assume that the barbell is lifted to a height of 2.0 meters.
Formula Needed: Work =
In this problem:
Force = 1600 N
Distance = 2.0 m
Therefore the Equation you must set-up is:
Work =
Work = 3200 Joules
Section III: Section 15.1
Key Terms
· Energy
· Kinetic Energy
· Potential Energy
· Gravitational Potential Energy
· Elastic Potential Energy
· Mechanical Energy
· Thermal Energy
· Chemical Energy
· Electrical Energy
· Electromagnetic Energy
· Nuclear Energy
Key Points
· Energy is the ability to do work.
· When work is done on an object, energy is transferred to that object.
· The energy of motion is called Kinetic Energy.
· Potential Energy is energy that is stored as a result of position or shape
· An objects potential energy depends on its mass, its height, and the acceleration due to gravity.
· The potential energy of an object that is stretched or compressed is known as Elastic Potential Energy.
· The energy associated with motion and position of everyday objects is mechanical energy.
· The total potential and kinetic energy of all the microscopic particles in an object make up its thermal energy.
· Chemical Energy is the energy stored in chemical bonds.
· Electrical Energy is the energy associated with electric charges
· Electromagnetic Energy is a form of energy that travels through space in the form of waves
· The energy stored in atomic nuclei is known as Nuclear Energy.
· The unit of energy is the Joule.
Practice Problems
1. Calculate the kinetic energy of a 0.25-kg toy car traveling at a constant velocity of 2 m/s.
2. Calculate the potential energy of a 3-kg pendulum that is held 2 m in the air.
3. Calculate the Kinetic energy of a 1.5 kg remote control car that is traveling at a constant velocity of 5 m/s.
4. Calculate the velocity of a pendulum using the following data.
- Mass = 2 kg
- Height = 2 meters
5. Calculate the velocity of a pendulum using the following data.
- Mass = 4 kg
- Height = 5 meters
6. John has an object suspended in the air. It has a mass of 50 kilograms and is 50 meters above the ground. How much work would the object do if it was dropped?
7. Calculate the work done by a weight lifter who lifts 100 kilograms 2 meters off the ground.
*In addition to this study guide be sure to study all class notes and assignments. This includes the reading and questions that you did in Section 15.1 of your Textbook. *