Chapter 7: Energy (From Lecture Slide) Flashcards
Energy
A property that can be used to determine how an object can change its state of motion or its physical shape
Energy existed in
Potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms
All forms of energy are associated with
Motion
Principle conservation of energy
Energy can be neither created nor destroyed but only changed from one form to another
Energy is the property of a system that enables it to do
Work
Energy observed when it is
Being transferred or being transformed
Energy any given body has kinetic energy if it is in
Motion
A bow or spring has the potential for creating
Motion; it contains potential energy
Nuclear energy is
Potential energy becuase it results from the configuration of subatomic particles in the nucleus of an atom
Energy (Definition) is the
Property of a system that can be used to do work or to heat
Energy can be transferred but
Total amount in the universe does not change
Work
How long the force acts over a distance
Matter is
Substance we can see, smell, and feel and has mass and occupies space
Impulse
How long the force acts over time interval
A transfer of energy over a distance by
Some applied external force
Work are include three mains part of the conceptually
1) Involves force and distance
2) Is force times distance
3) In equation form: W = Fd
Two things occur whenever work is done:
1) A force acts on an object
2) The object subject to the force
If you push against a stationary brick wall for several minutes, you do not work
You may do work on your muscles, which stretch and contract, but not on the wall because the wall does not move
Twice as much work is
Done in lifting two loads 1 story high versus lifting 1 load the same vertical distance
Why twice as much work is?
Force needed to lift twice, the load is twice as much
Is there work being done in lifiting the barbell?
There is a force required to lift the weight of the barbell off the ground to a distance above the weightlifter’s head.
Work is done in lifiting a barbell. How much work is done in lifting a barbell that is twice as heavy the same distance?
This is in accord with work equals to the force x distance. Twice the force for the same distance means twice the work done on the barbell
You do work when pushing a cart with a constant force. If you push the cart twice as far, then the work you do is
Twice as much
A job can be done slowly or quickly. These methods require the same amount of work, but different amounts of
Power is the rate of which work is done, so doing the job faster requires more power
