the big idea energy is transferred when a force moves an object. work and energy work is the use of...
TRANSCRIPT
thethe BIGBIG ideaidea
Energy is transferred when a force moves an object.
Work and Energy
Work is the use of force to move an object.4.14.1
Energy is transferred when work is done.4.24.2
Power is the rate at which work is done.4.34.3
CHAPTER
CHAPTER OUTLINE
NEW CHAPTER
VOCABULARY
KEY CONCEPT CHAPTER HOME
Work is done by a force that acts in the same direction as the motion of an object.Work = Force • distance
4.14.1
SECTION OUTLINESECTION OUTLINE
Work is the use of force to move an object.
joule
work
applied force
object
direction of motion
part of force doing work
part of force not doing work
object
applied force
direction of motion
VOCABULARY
KEY CONCEPT CHAPTER HOME
Top of Ramp100%PE
1
At the top of the ramp, the skater’s mechanical energy is equal to her potential energy because she has no velocity.
The amounts of potential energy and kinetic energy in a system or process may vary, but the total amount of energy remains unchanged.
Energy is transferred when work is done.4.24.2
SECTIONOUTLINESECTIONOUTLINE
kinetic energy
mechanical energy
conservation of energy
potential energy
GPE = mgh
ME = PE + KE
KE = mv21
2
VOCABULARY
KEY CONCEPT CHAPTER HOME
The amounts of potential energy and kinetic energy in a system or process may vary, but the total amount of energy remains unchanged.
Energy is transferred when work is done.4.24.2
SECTIONOUTLINESECTIONOUTLINE
kinetic energy
mechanical energy
conservation of energy
potential energy
GPE = mgh
ME = PE + KE
KE = mv21
2Halfway Down Ramp2
50%KE
50%PE
As the skater goes down the ramp, she loses height but gains speed. The potential energy she loses is equal to the kinetic energy she gains.
VOCABULARY
KEY CONCEPT CHAPTER HOME
The amounts of potential energy and kinetic energy in a system or process may vary, but the total amount of energy remains unchanged.
Energy is transferred when work is done.4.24.2
SECTIONOUTLINESECTIONOUTLINE
kinetic energy
mechanical energy
conservation of energy
potential energy
GPE = mgh
ME = PE + KE
KE = mv21
2Bottom of Ramp
100% KE
3
As the skater speeds along the bottom of the ramp, all of the potential energy has changed to kinetic energy. Her mechanical energy remains unchanged.
VOCABULARY
KEY CONCEPT CHAPTER HOME
Power can be calculated from work and time.
4.34.3
SECTIONOUTLINESECTIONOUTLINE
Power is the rate at which work is done.
watt
power
horsepower
Power = Worktime
Power can be calculated from energy and time.
Power = Energytime
Power is measured in watts (W) and sometimes horsepower (hp).
VOCABULARY
KEY CONCEPT CHAPTER HOME
1. Force, Motion, and Work
I. Work is the use of force to move an object.
A. Force is necessary to do work.
B. Objects that are moving can do work.
2. Calculating Work
4.14.1
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
Work is the use of force to move an object.
joule
work
VOCABULARY
KEY CONCEPT CHAPTER HOME
II. Energy is transferred when work is done.
A. Work transfers energy.
C. The total amount of energy is constant.
4.24.2
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
B. Work changes potential and kinetic energy.
1. Calculating Gravitational Potential Energy
Energy is transferred when work is done.
2. Calculating Kinetic Energy
3. Calculating Mechanical Energy
1. Conserving Mechanical Energy
2. Losing Mechanical Energy
3. Forms of Energy
kinetic energy
mechanical energy
conservation of energy
potential energy
VOCABULARY
KEY CONCEPT CHAPTER HOME
III. Power is the rate at which work is done.
A. Power can be calculated from work and time.
1. Calculating Power from Work
B. Power can be calculated from energy and time.
4.34.3
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
Power is the rate at which work is done.
2. Horsepower
1. Calculating Power from Energy
2. Everyday Power
watt
power
horsepower