# Physical Science Chapters 3 & 4

Flashcard maker : Lily Taylor
The energy an object has because of its position is called potential energy.
True
Energy is not conserved when a moving object slows to a stop.
False
A spring-loaded paper clamp exerts a force of 2 N on 10 sheets of paper it is holding together. Is the clamp doing work as it holds the papers together?
No
Kinetic energy refers to
energy of motion
You can find the energy of a book of a certain mass just before it hits the floor after falling a certain distance by using which equation?
PE = mgh
Two students are poised to dive off equal height diving towers to a swimming pool below. Student B is twice as massive as student A. Just before hitting the water, student B will have…
twice as much kinetic energy as student A.
A car is moving straight down a highway under ideal conditions. What factor has the greatest influence on how much work must be done on the car to bring it to a complete stop?
How fast it is moving.
Two identical cars are moving straight down a highway under identical conditions, except car B is moving three times as fast as car A. How much more work is needed to stop car B?
Nine times as much.
The solar technology that is today contributing about as much energy as moving water is
biomass
Which form of energy does not require matter for traveling through space?
Roughly, what fraction of our nation’s current energy needs is supplied by coal?
20%
In all of our energy uses, we find that…
the total amount of energy is constant in all situations.
The watt (W) is a unit of…
power
The potential energy of a box on a shelf, relative to the floor, is a measure of…
-the energy the box has because of its position above the floor
-the weight of the box times the distance above the floor
-the work that was required to put the box on the shelf from the floor
The basic premise of a simple machine is that work in equals work ___________?
out
Does a person do more work walking up stairs or running up stairs?
same
There are two sets of units that may be used when talking about “power.”

When finding the amount of power using pounds times feet per second, power is measured in horsepower.

However, when measuring power in newtons times meters per second, the amount of power is expressed in what unit?

watts
Energy can do work AGAINST a combination of forces: inertia, gravity, friction, and/or shape.

When a chair is being pushed in, energy does work against friction and which other?

inertia
Any form of energy can be converted to another, but energy used on Earth usually ends up in this form of electromagnetic energy, called __________.
Today, the basic problem with using solar cells as a major source of electricity is
manufacturing cost
*Molecules* are the *smallest units of matter* with the
*characteristic* properties of a *substance*.
True
Water beads up on wax paper because its *cohesive* forces are *greater* than the *adhesive* forces.
True
The attractive forces between unlike molecules is called…
Molecules in a solid…
are held in nearly fixed positions by strong attractive forces
Anytime a *temperature difference* occurs, you can expect…
*heat movement* from *high temperature* regions.
The molecules of a gas are much closer together than molecules in a solid or liquid.
False
*Liquid water* at 0ºC has to *give up energy* in order to *become ice* at 0ºC.
True
When water vapor condenses to a liquid…
it transfers heat to the surroundings.
When the *evaporation* rate *equals* the *condensation rate*, the space above the liquid is…
saturated
When you add heat to a substance the temperature…
might stay the same
The great cooling effect produced by water evaporating comes from its high…
latent heat
The transfer of heat that takes place by energy moving through space is called convection.
False
The transfer of heat that occurs when energy moves from molecules to molecule is called…
conduction
A liquid at 20ºC is twice as hot as the liquid at 10ºC.
False
A temperature of 100oC is the equivalent to…
373 K
Iron heats up more rapidly than does aluminum because it has a greater specific heat.
False
The heat needed to warm one gram of water one Celsius degree is called a…
calorie
The water in a swimming pool is cooler than the surrounding sidewalk because it…
has a higher specific heat
A *statement* that the *energy supplied* to a system in the *form of heat*, *minus the work* done by the system, is *equal* to the *change in internal energy* represents the…
first law of thermodynamics.
The heat death of the universe is a theoretical time in the future when the universe is supposed to…
freeze at a uniform low temperature.