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112 terms

Physical Science Fall 2010 Exam

Vocab and concepts needed for the fall 2010 exam
An organized way of using evidence to learn about the natural world
the practical application of science to commerce or industry
scientific method
a method of investigation involving observation and theory to test scientific hypotheses
scientific model
a representation of an object or event that can be studied to understand the real object or event
frame of reference
A system of objects that are not moving with respect to one another.
change in position of an object, distance and direction of an object's change in position from the starting point
distance travelled per unit time, measured in m/s
the rate at which velocity changes over time; if an object's speed, direction, or both change, measured in m/s2
a push or pull exerted on an object
a force that opposes motion between two surfaces that are touching
static friction
the friction that acts on objects that are not moving
sliding friction
friction that occurs when one solid surface slides over another
fluid friction
force exerted on an object due to a liquid or a gas
air resistance
the fluid friction experienced by objects falling through the air
a force of attraction between objects that is due to their masses
terminal velocity
the greatest velocity a falling object reaches
the tendency of an object to resist a change in motion
the amount of matter in an object
A measure of the force of gravity on an object
force or energy that keeps something moving, a measure of how hard it is to stop a moving object
electromagnetic force
attraction or repulsion between charged particles
strong nuclear force
a powerful force of attraction that acts only on the neutrons and protons in the nucleus of an atom, holding them together
weak nuclear force
responsible for breaking up and decaying radioactive elements
gravitational force
the force of attraction between all masses in the universe
centripetal force
any force that causes an object to move in a circular path
the force applied to a unit area of surface
any substance that can flow
an upward force
The ability of an object to float or rise in a liquid or gas
Archimede's principle
The buoyant force on an object is equal to the weight of the fluid displaced by the object.
Bernoulli's principle
As the speed of a fluid increases, the pressure within the fluid decreases.
Force x Distance
a device that can multiply force.
mechanical advantage
the number of times that a machine increases an input force
a simple machine consisting of a rigid object that pivots about a fixed point
the fixed point around which a lever pivots
wheel and axle
a simple machine that has a center rod attached to a wheel
inclined plane
a simple machine consisting of a flat surface with one end higher than the other
An inclined plane that moves. MA increases as it becomes longer and thinner. Ex: Knife, Axe, Door stopper
simple machine that consists of an inclined plane wrapped in a spiral around a cylindrical post
a simple machine that consists of a rope that fits into a groove in a wheel
compound machine
a device that combines two or more simple machines
the ability to do work
kinetic energy
energy of motion
potential energy
energy stored due to an object's position
elastic potential energy
potential energy that is stored when a body is deformed (as in a coiled spring)
mechanical energy
the energy associated with the motion and position of everyday objects
thermal energy
the total kinetic and potential energy of all the particles in a substance.
chemical energy
energy stored in chemical bonds
electrical energy
the energy of moving electric charges
electromagnetic energy
energy that travels through space as waves, energy of light and other forms of radiation
nuclear energy
energy stored in the nucleus of an atom
fossil fuels
coal, oil, natural gas, and other fuels that are ancient remains of plants and animals.
hydroelectric energy
electrical energy produced by falling water
solar energy
energy from the sun that is converted into thermal or electrical energy
geothermal energy
energy derived from the heat in the interior of the earth
biomass energy
the chemical energy stored in living things
hydrogen feul cell
Generates electricity by reacting hydrogen with oxygen.
nonrenewable energy resource
is a source of energy that exists in limited quanities and, once used, cannot be replaced except over the course of millions of years.
The gravitational force between two objects increases as mass....
increases or distance decreases.
energy=mass times speed of light squared
True Statements: Mass and energy are equivalent. Energy is released when matter is destroyed.
True Statement: The law of conservation of energy must be modified to state that mass and energy are conserved in any process.
As an astronaut travels far away from Earth, her weight
decreases because gravity decreases.
The gravitational potential energy of an object is always measured relative to the
reference level from which the height is measured.
Where will the greatest increase in pressure occur if you squeeze the middle of an upright, closed soft-drink bottle?
The pressure will increase equally everywhere within the bottle.
Your weight equals your...
mass times the acceleration due to gravity.
A 750-W motor might also be rated as how many horsepower?
1-horsepower motor.
A cork is floating in salty water. As more salt is added to the water to increase its density, the cork will...
float at a higher level in the water.
An open parachute increases air resistance of a falling sky diver by...
increasing surface area.
The power of a machine measures....
its rate of doing work.
What about Bernoulli's principle makes gives lift to an airplane wing in flight?
Air above the wing travels faster than air below the wing.
The property of matter that resists changes in motion is called....
Objects in free fall near the surface of the Earth experience...
constant acceleration.
Where is fluid pressure greatest?
The deeper you go in a fluid, the greater the pressure.
When an unbalanced force acts on an object,
the object accelerates.
The ideal mechanical advantage of a pulley system is equal to the
number of rope segments supporting the load.
What does the prefix kilo- mean?
A ball is rolled uphill a distance of 5 meters before it slows, stops, and begins to roll back. The ball rolls downhill 10 meters before coming to rest against a tree. What is the magnitude of the ball's displacement?
5 meters
An inclined plane reduces the effort force by...
increasing the distance through which the force is applied.
A person drives North 9 blocks, then turns , and drives West 9 blocks. The driver then turns South and drives 9 blocks. How could the driver have made the distance shorter while maintaining the same displacement?
Driving 9 blocks West of the starting point.
The Law of Conservation of Energy
Energy cannot be destroyed.
Energy cannot be created.
Energy can be converted from one form to another.
What is transferred by a force moving an object through a distance?
A benefit of a hydrogen fuel cell is that its byproduct is...
Atmospheric pressure is caused by...
the weight of the atmosphere above a particular location.
What force is responsible for the repulsion between two positively-charged particles?
When a pair of balanced forces acts on an object, the net force that results is...
equal to zero.
What is the most important safety rule?
Always follow your teacher's instructions and textbook directions exactly.
Besides the weak nuclear force, is gravity the strongest or weakest universal force?
weakest... it is weaker than the strong force, electric force, and the magnetic force.
A drawback of solar energy is that it....
Depends on the weather / climate.
The actual mechanical advantage of a machine...
is ALWAYS less than the ideal mechanical advantage of the machine.
Two identical corks float in separate beakers. One beaker contains distilled water. The other contains very salty water. Are they both subject to the same buoyant force even though they are in different fluids?
The cork in salty water may float higher because the salt water is more dense than the distilled, but if the corks are exactly the same they will both be subject to the SAME buoyant force.
Reducing friction in a machine...
increases its efficiency.
The hydraulic system of a dump truck is designed to multiply...
Why does a hot-air balloon float?
The weight of the balloon is less than the weight of the air displaced by the balloon.
As you push a cereal box across a tabletop, the sliding friction acting on the cereal box...
acts in the direction opposite of motion.
If you know the input distance and output distance of a machine, which of the following can you calculate?
ideal mechanical advantage
How can a machine make work easier for you?
by changing the direction of your force
Where does does Einstein's famous equation (E=mc2) apply?
nuclear fission and fusion reactions, where matter is converted to energy.
Why is the gravitational potential energy of an object 1 meter above the moon's surface less than its potential energy 1 meter above Earth's surface?
The object's acceleration due to gravity is less on the moon.
Work is a transfer of what?
Why are scientific models important?
They help visualize things that are very complex, very large, or very small.
When opposite poles of two magnets are brought together, the poles...
attract each other.
The acceleration due to gravity on the surface of Mars is about one third the acceleration due to gravity on Earth's surface. The weight of a space probe on the surface of Mars is about...
one third its weight on Earth's surface.
The mechanical energy of an object equals its....
kinetic energy plus its potential energy.
The total potential and kinetic energy of all the MICROSCOPIC particles in an object make up its...
thermal energy.
How can you increase POWER?
To increase power, you can increase the amount of work you do in a given amount of time, or you can do a given amount of work in less time.
How are science and technology related?
Advances in science may lead to advances in technology and vice versa.
A force acting on an object does no work if
the force is not in the direction of the object's motion.
An object that is accelerating may be...
speeding up, slowing down, or changing direction.
The efficiency of a machine is always less than 100 percent because...
some work input is ALWAYS lost to friction.
An orange might roll off your cafeteria tray when you stop suddenly because of...
the orange's inertia.
Fossil fuels currently account for the majority of the world's energy use because they are...
relatively inexpensive and readily available.