Exam study modules 9-15

Resistance

A material's opposition to the flow of electric current.

Would you rather buy Christmas tree light strands that are wired in a parallel or a series? WHY?

A parallel circuit b/c if one bulb goes out the others will still stay lit. B/c the flow is not cut off.

vector quantity

A physical measurement that contains directional information.

scalar quantity

A physical measurement that does not contain directional information.

Photon

A small "package" of light that acts like a particle.

longitudinal wave

A wave that's propagation of direction is parallel to the directions oscillation.

transverse wave

A wave that's propagation of direction is perpendicular to the direction of oscillation.

You are looking in a scientist's lab note book and you find the following unlabeled measurements. In each case, determine what physical quantity the scientist was measuring. A. 12.1 meters per second B. 31.2 feet C. 14 millimeters per hour to the West's D. 4.5 yards per minute squared north.

A. 12.1 meters per second= scalar, speed B. 31.2 feet= scalar, distance C. 14 millimeters per hour to the West's= vector, velocity. D. 4.5 yards per minute squared north= vector, acceleration.

After a visit to see your relatives, you get in your car to go home. You are in the front passenger seat and your dad is driving. As you dad is backing off the driveway, your relatives all come out to say good bye. A. Who is in motion relative to you? B. Who is motionless relative to you?

A. = your relatives. B.= your dad.

Mrs. V is on a roller coaster, which rapidly picks up speed as it rolls down a slope. As it starts down the slope it's speed is 4 meters per second. But 3 seconds later, at the bottom of the slope, her speed is 22 meters per second. What is the average acceleration?

A=( Vf-Vi)/time. A=22m/s-4m/s/3s= 6 m/s squared down hill.

What is the acceleration of an object that moves with a constant velocity?

Acceleration=0

Newton's first law

An object in motion or at rest will tend to stay in motion or at rest until acted soon by an outside force.

Supersonic speed

Any speed that is faster than the speed of sound in the substance of interest.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Why must one use a reference point to determine whether or not an object is in motion?

B/c it could be moving from different reference points, so we say which one we are using.

Why does a dropped feather hit the ground later than a rock dropped at the same time?

B/c the feather has more air resistance.

science fiction movies often use the term in space no one can hear you scream. Why is that statement true?

B/c there is no air for sound to travel through.

A physicist changes an object with a positively charged rod. If the object develops a negative charge, how did the physicist charge the object?

By induction.

What are comets composed of?

Dirt, ice, metal, dust.

What is the geocentric theory?

Earth is the center of the Universe

Newton's third law

For every action there is an equal and opposite reaction.

kinetic friction

Friction that opposes motion once the motion has already started.

static friction

Friction that opposes the initiation of motion.

A women pushes a box (mass= 80 kilograms). The static friction between the box and he ground is 20 Newtons, while the kinetic friction is 7 Newtons. How much force must the women exert to get the box moving? With what force must she push the box in order to get it to accelerate at 1.0 m/s squared to the west?

Ft=Fk+F M•A Force to get moving = 20 Newtons =7w+80kg•/sec2=80 =87N west

What medium dose sound move slowest through? Why?

Gas b/c air molecules are farther apart.

What theory did Galileo come up with? Why did he think it was correct?

Geocentric, b/c he saw the earths shadow on the moon.

List 2 ways you can reduce friction.

Ice, sand the surface.

Who came up with the universal law of gravitation?

Isaac Newton

Name the outer planets.

Jupiter,Saturn,Uranus,Neptune.

Which planet in the solar system revived the greatest amount of insolation?

Mercury

Name the inner planets.

Mercy, Venus,earth, mars.

A huge pile of leaves is wrapped in a tarp in the middle of the lawn. The wrapped leaves weigh 580 newtons. How much force is required to start sliding the wrapped leaves?

More than 580 N, enough to overcome the static friction.

Name the main particles that are found on an atom, and where in the atom are they located?

Neutrons and protons are found in the nucleus, electrons are found orbiting the nucleus.

Which of Newton's laws of motion would explain why a football sits on the ground without moving until you put a force on it?

Newton's first law.

Is centrifugal force a real force?

Nope

What parts are always present?

Nucleus and coma

Do sound waves oscillate parallel or perpendicular to the direction in which air travels?

Parallel

What are the horizontal rows on the chart called?

Periods

List one was to increase friction.

Rough the surface.

Why would you want to decrease friction?

So that something can slide better.

What medium dose sound move fastest through? WHY?

Solid b/c air molecules are closer together.

A comet is cruising through the solar system at a speed of 50,000 kilometers per hour for 4 hours time what is the total distance traveled by the comet during this time.

Speed= distance/time. Speed= 50,00 km/ 4km • 4h Then cancel out the hours. = 2000000km

What is the heliocentric theory?

Sun is the center of the universe

You are blindfolded and handed 2 extension cords of equal length. Both have the same current running through them. If the cord in your right hand is warmer than the cord in your left hand what can you conclude?

That the left cord is thicker.

electrical current

The amount of charge that travels past a fixed point in an electric circuit each second.

What separate the inner and outer planets?

The astroid belt.

When baseball players hit the ball hard enough, there bats can sometimes break. What is exerting a force on the bat, causing it to break?

The ball.

What is the name of the system that places the elements into an organized way to study? Who developed the system?

The periodic table of elements. Mendeleeve

A pilot is flying A mission to drop bombs on an enemy Feild. The plane is flying high and fast to the north, and the city is due north. Should the pilot drop the bombs before the plane is over the airfield, when she plane is over the airfield, or after the plane has passed the air Feild?

The pilot should drop the bomb before he is over the airfield.

Acceleration

The time rate of change of an object's velocity.

Newton's second law

When an object is acted on by one or more outside forces, the total force is equal to the mass of the object times the resulting acceleration.

The atoms in an object are alighted is this object a magnet?

Yes.

If a piece of paper is placed between a radioactive isotope and a person, which kind of radioactive particle will the person be protected from?

alpha particles

What are the parts of a comet?

coma, nucleus, tail

Which is the weakest of the fundamental forces?

gravitational force

atomic number

the number of protons in an atom.

mass number

the sum of the number of neutrons and protons in an atomic nucleus.

You cut a magnet in half-right between the north and south poles. How many north and south poles do you now have?

2 of each.

An eagle swoops down to catch a baby rabbit. Luckily for the rabbit, he sees the eagle and runs. An all out chase ensues with the rabbit running west at 5.4 meters per second and the eagle pursing at 4.4 meters per second. what is the relative velocity of predator and prey?

5.4m/s West- 4.4m/s West= 1m/s west

You are looking through a physicists laboratory notebook and notice 2 numbers for the friction between a block of wood and a laboratory bench. The numbers are 8 Newtons and 11 Newtons. Which refers to static and which refers to kinetic?

8=Fk 11=Fs