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33 terms

Chapter 4 test; "Work and energy"

STUDY
PLAY
Energy does not have to involve motion
True
Energy is the ability to cause a change
True
Energy is the ability to cause change
True
when you ride a playground sing, your potential energy is greatest at the highest point
True
Chemical energy travels from the sun to Earth and is transformed into light energy by plants
False
As mass decreases. kinetic energy increases
False
Lowering an object decreases its potential energy
True
In a car engine, buring fuel produses heat. which causes gases to expand. producing kinetic energy
False
The sum of potential and kinetic energy in a system is called the total energy
False
As an object falls its potential energy is lost to the air around it
True
Carbohydrates and fats provide our bodies with energy in the form of calories
True
Energy from the sun and energy from food are just different forms of the same thing
True
Under certain conditions it is possible to get more work out of a machine than you put into it
True
Some machines do not multiply the force that is applied to them
True
In order for qork to be done on an object the object must move
True
Power equals work myltiplied by time
False
Mechandical advantage is always greater than 1
False
Energy cannot be changed from one variety to another
False
Gravitational potential energy is proportional to both mass and height above a reference lever
True
A stretched bow and a compressed rubber ball both possess elastic potential energy
True
The kinetic energy of an object increases as its ___ increases
Mass
Invresing the speed of an object __ Its potential energy
Decreases
The SI unit for energy is the ____
Joule
You can calculate kinetic energy by using the equasion
M*V2 / 2
You can calculate gravitational potential energy by using the equasion ____
MH.8 m/s2
A bus engine transgers chemical potential energy into ____ so that the bus moves
Kinetic energy
According to the law of conservation on energy, the total amount of energy in the universe ____________
Does not change
A device that does work with only one movement and changes the suze or direction of a force is a ____
Machine
The amount by which a machine multiplies an effort force is called the ______
Mechanical energy
When two or more simple machines work together, they are called _________
Compound machine
Unit of power is the _____
Watt
Machines make tasks easier by changing either the magnitude or the direction of the _______ needed
Force
At what point is a rollercoasters GPE the lowest?
Closest to the ground