a method of investigation involving observation and theory to test scientific hypotheses
a representation of an object or event that can be studied to understand the real object or event
change in position of an object, distance and direction of an object's change in position from the starting point
the rate at which velocity changes over time; if an object's speed, direction, or both change, measured in m/s2
force or energy that keeps something moving, a measure of how hard it is to stop a moving object
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
The buoyant force on an object is equal to the weight of the fluid displaced by the object.
As the speed of a fluid increases, the pressure within the fluid decreases.
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
elastic potential energy
potential energy that is stored when a body is deformed (as in a coiled spring)
energy that travels through space as waves, energy of light and other forms of radiation
coal, oil, natural gas, and other fuels that are ancient remains of plants and animals.
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.
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.
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.
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.
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 ideal mechanical advantage of a pulley system is equal to the
number of rope segments supporting the load.
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?
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 force is responsible for the repulsion between two positively-charged particles?
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.
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.
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
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.
Why are scientific models important?
They help visualize things that are very complex, very large, or very small.
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 total potential and kinetic energy of all the MICROSCOPIC particles in an object make up its...
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.
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.