A liquid mixture in which particles can be seen and easily separated by settling or filtration is a...
How is a solute different from a solvent in a solution?
The solute is present in a smaller amount
Weak tea is an example of a...
When you add so much solute that no more dissolves, you have a...
What is one way to increase the solubility of sugar in water?
heat the water
What is a characteristic property of acids?
They turn blue litmus paper red
Acids are described as corrosive because they...
"eat away" at other materials
Which is a likely use for a base?
making soups and detergents
In a water solution, how do acids differ from bases?
Acids from hydrogen ions (H*),while bases from hydroxide ions (OH-)
In water, bases form...
The pH scale measures...
the concentration of hydrogen ions
Neutralization is a reaction between a(n)...
acid and a base
What does a neutralization reaction produce?
water and a salt
Normal rainfall is slightly acidic, which means its pH must be...
between 5 and 7
When a solid compound dissolves in water...
each of its particles becomes surrounded by water molecules
A measure of how well a solute can dissolve in a solvent at a given temperature is that substance's...
Acids naturally present in food are safe to eat because they usually are...
You can find the pH of a substance by using...
What happens when two forces act int eh same direction?
they add together
The tendency of an object to resist change in its motion is known as...
The greater the mass of an object...
the greater the inertia
The force of gravity on a person or object on the surface of a planet is called...
The force that one surface exerts on another when the two rub against each other is called...
When of the following is an example of rolling friction?
bike tires on the road as you ride
When the only forace acting on a falling object is gravity, the object is said to be...
in free fall
Air resistance is a type of...
The froce of gravity on a person or object at the surface of a planet is known as...
The force of gravity on a person or object at the surface of a planet is known as...
Forces can be added together only if they are...
acting on the same object
The product of an object's mass and velocity is called its...
The achievement of lifting a rocket off the ground and into space can be explained by...
Newton's third law
What is required for a rocket to lift off into space?
thrust that is greater then Earth's gravity
In physical science, a push or a pull is called a(n)...
The momentum of an object is in the same direction as its...
How can you increase the momentum of an object..
by increasing its mass
The amount of matter in an object is called its
Whch of the following is an example of increasing friction intentionally?
throwing sand on an icy driveway
The force that pulls faling objects toward Earth is called...
Objects falling through air experience a type of friction called...
According to Newton's thrid law of motion, when a hammer strikes and exerrts force on a nail, the nail...
exerts an equal force back on the hammer
The SI unit for force is the...
When an objects's distance from another object is changing...
it is in motion
The basic SI unit of length is the...
Speed equals distance divided by...
When you know both the speed and direction of an object's motion, you know the...
velocity of the object
You can show the motion of an object on a line graph in which you plot distance against...
The steepness of a line on a graph is called the...
The reate at whch velocity changes is called...
To determine the acceleration rate of an object, you must calculate the change in speed during each unit of...
If speed is measured in kilometers per hour and time is measured in hours, the unit of acceleration is...
kilometers per hour per hour
Average speed is...
the total distance traveled divided by the total time
On a graph showing distance vs. time, a horizontal line represents an object tha is...
not moving at all
The Internation System of Units is used...
all over the world
If you know the distance an object has traveled in a certain amount of time, you can determine...
the speed of the object
It is rare from any motion to...
stay the same for very long
If the speed of an object does NOT change, the object is traveling at a...
Changing direction is an example of a kind of...
If a bicyclist travels 30 kilometers in two hours, her average speed is...
If an object moves in the same direction and at a constant speed for 4 hours, whch of the following is true?
the objects velocity did not change
If you know a car traveled 300 kilometers in 3 hours, you can find its...
In an acceleration graph showing speed vs. time, a straight line shows the acceleration is...
For work to be done on an object...
the object must move some distance as a result of a force
Which of these is an example of work being done on an object...
pushing a child on a swing
If you exert a force of 20 newtons to push a desk 10 metersm how much work do you do on the desk?
Work is meausured in...
What do machines do?
change the amount of force you exert or the distnace over whch you exert the force
Pulling down a rope to hoist a sail on a sailboat is an example of a machine...
changing the direction over whch a force is exerted
Without friction there would be...
equal input and output work
An ideal machine would have an efficiency of...
A ramp is an example of a simple machine called a(n)...
The ideal mechanical advantage for an inclined plane is equal to the length of the incline divided by the...
height of the incline
Which of these is an example of a third-class lever?
The ideal mechanical advantage of a wheel and axle is equal to the...
radius of the wheel divided by the radius of the axle
A machine that utilizes two or more simple machines is called a...
One example of a compound machine is a...
Which boy parts act as the fulcrums of levers?
Whch body parts are shaped like wedges?
A simple machine that might be thought of as an inclined plane that moves is a...
Which of these could be considered an inclined plane wrapped around a cylinder?
The fixed point that a lever pivots around is called the...
In order to do work on an object, the force that you exert must be...
in the same direction as the object's motion
Work equals force times..
When you raise or lower a flag on a flagpole, you are using a(n)...
How can a hockey stick be considered a machine?
it multiplies distance
The mechanical advantage of a machine that change only the direction of force is...
Most of hte machine in your body consist of bones and muscles and are called...
If tight scissors have an efficiency of 50%, half you work is wasted due to...
The power of a light bulb that converts electrical energy at a rate of 100 joules per second is...
Power is measured in units called...
The wedge, screw, and lever are all...
Everyday we are surrounded by radiation called ____________ radiation.
Gamma radiation is represented by the symbol...
The number of protons in the nucleus of an atom is called its _________.
Nuclear pwoer plants make use of the nuclear process called __________.
The symbols a or He are used to represent ____ radiation...
The number of protons plus the number of neutrons in the nucleus of an atom is called its...
The process in which serveral small nuclei combine to make a larger nucleus is called...
The symbol B is used to represent ________ radiation.
The half-life of a radioactive isotope is the itme it takes for _____ of the radiation in a sample to disappear.
The nucleus of the atom is split during nuclear ________.
The nucleus of an atom that releases radiation of any kind is said to be ______.
A beta particle is simply a high speed _____ ejected from the nucleus.
Whch form of nuclear radiation is not a partilce?
A solute is a mixture which partilces can be seen and easily separated
A substance that is present in a solution in a smaller amount and is dissolved by the solvent is called the solute.
Amoung the factors that affect the solubility of a substance are type of solvent, pressure,and time.
Because solubility is a characterisitic property of matter, it can be used to help identify a substance.
Bases feel slippery and taste sour.
Bases form hydrogen ions (H*) when dissolved in water.
The particles in suspension are larger than the particles in a solution but are still too small to be seen easily.
The products of a neutralization raction are acids and bases.
Unbalanced forces do not change an object's motion.
The property of matter that resists a change in motion is called inertia.
According to Newton's second law of motion, weight depends on an object's mass and the net force acting on the object.
Friction depends on the types of surfaces involved and how hard the surfaces push together.
Mass and air resistance affect the gravitational attration between objects.
When the only force acting on a falling object is air resistance, the object is said to be in free fall.
Newton's thrid law of motion states that for every action there is an equal but oppostie unbalanced force.
A unit of momentum is kg x m/s.
A rocket will move upward as long as the thrust is greater then the force of gravity.
The force that keeps a satellite in Earth's orbit is always directed away from the center of Earth.
Motion is meaured relative to a reference point.
Average speed is the rate at which an object is moving at a given instant
A meter is a place or object used for comparison to determine if something is in motion.
If a toy car traveling at 10 cm/s passes a toy car moving at 10 cm/s in the opposite direction, both cars have the same velocity.
A straight diagonal line on a distance versus time graph indicates constant speed.
A horizontal line on a distance versus time graph means tha tthe object is at rest.
A child riding a merry-go-round is accelerating because his direction is changing.
The SI unit of velocity is the meter per second per second.
A straight line of a graph of speed versus time means that he object has a constant acceleration.
Holding a 25-N bag of sugar 1 meter from the floor requires 25 joules of work.
The forece exerted by a machine is called the output force.
The mechanical advantage of a machine that changes only the direction of a force is 1.
Efficiency compares the output work to the output force.
A wheel and axle is a compound machine.
A second-class lever always multiplies distance.
The ideal mechanical advantage of a wheel and axle is the radius of the wheel times the radius of the axle.
When you raise your leg, the knee acts as a fulcrum for the upper leg.
You do work on an object when you lift it from the floor to the shelf.
Energy is the rate at which work is done.
Use the pH scale to compare an apple and a lemon.
Lemons have a pH of about 2 and apples have a ph of about 3. A lemon is more acidic.
In terms of pH, explain what would happen if you mixed vinegar with a solution of ammonia?
Vinegar is an acid and ammonia is a base, so neutralization would occur.
What does the pH of drain cleaner tell you about the dangers of such a product?
a high pH means that drain cleaner is very acidic.
Why would you expect soap to taste bitter?
Soap is a bease,and bases taste bitter.
What two variable are plotted in the graph?
distance and time
How would you describe Kathy's motion? What does such motion mean?
Kathy is jogging at a constant speed. Her speed doesn't change as she moves.
How far did Kathy jog int he first four minutes?
What is Kathy's average speed?
How long after Kathy started jogging did Rachel begin jogging?
Describe Rachel's motion in 9 minutes.
Rachel isn't moving; she is at rest.
What two variables are plotted on the graph?
speed and time
What does the line segment on the graph from 0 to 3 seconds represent? Explain you answer.
The segment represents constant acceleration. The speed increases by the same amount during each second.
What is the acceleration of the ball between 0 and 3 seconds?
What happened to the speed of the ball during the final two seconds?
the ball's speed was constant; it didn't change.
Does the graph indicate that the ball decelerated? Explain your answer.
How far did the ball move in the final 2 seconds?
In what class is the direction of the input force opposite to the direction of the output force?
What class of lever is a piar of scissors? Explain your answer.
first-class because the fulcrum is between the input force and the output force.
To which class of lever does each of the following belong? (a) fishing pole; (b) wheelbarrow; (c) bottle opener; (d) pliers?
(a) third; (b) second; (c) second; (d) first
What would happen to the ideal mechanical advantage of the lever in diagram B if the output force were moved further from the fulcrum?
The ideal mechanical advantage would decrease
Why would it be impossible to build machine D?
The machine multiplies both force and distance. The output work of the machine would be greater than the input work, which is impossible because a machine cannot do more output work then input work.
Is machine 1 classified as a simple or compound machine?
What is machine 1 used for?
In machine 2, which letter reperesents the input force?
Which machines multiply the input force?
machines 2, 3, 4, and 5, because at least 2 sections of rope support the mass
Which machine has the greatest ideal machanical advantage?
machine 5, because a sections of the rope support the mass
Compare the distances and directions of the input force and output force in machine 4.
The input force moves downward 4 times as fast as the output forece moves upward.
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