P/E Science Final Exam

1. A figure skater is skating around a rink. a. Can he/she have a constant speed AND a changing velocity? Explain why or why not.a. Can he/she have a changing speed AND a constant velocity? Explain why or why not.

yes, because you're changing direction. no, because you are changing direction

Write the equation used to calculate the change in thermal energy and state what each variable stands for.

Q=change in temp•mass•specific heat

Use the formula Q=m*C*ΔT and table 2. How does the temperature of a 2.0 kg piece of graphite change when it absorbs 2,000J of thermal energy?

Q=m*C*ΔT 2,000=ΔT•2.okg•710C Q=0.71oC

Use the formula Q=m*C*ΔT and table 2. How much thermal energy is needed to raise the temperature of 4.0kg of water from 25oC to 75oC?

Q=m*C*ΔT Q=50•4.0kg•4,184C Q=836,800

Which part of the electromagnetic spectrum is usually used for communication today?

Radiowaves

a graduated cylinder has 10 ml of water in it. a marble with a mass of 10 grams is dropped into the cylinder. the water level rises to 30 ml. what is the density of the marble?

density=mass/volume d=10 g/20 m d=.5 g/ml

A truck travels to a stone quarry and then returns to its starting point. What is the distance the truck traveled? What is the truck's displacement?

distance- from stone quarry and home displacement- 0

EXPLAIN the difference between distance and displacement.

distance-an amount of space between things displacement-the moving of something from its place or position

Why does the Earth exert a stronger gravitational force than the moon?

earths gravity comes from all its mass

1. What type of power can be used in small, portable devices like calculators as well as entire buildings?

electric generators

What do sound waves carry?

energy

According to the entropy principle, any event that occurs in the universe must cause what to happen?

entropy increases, energy spreads out

Use the formula F=ma. A 300 N force acts on a 25 kg object. Calculate the acceleration of the object.

f=ma 300N=25kgXa a=12m/s2

Use the formula F=ma. Calculate your mass if a scale on earth reads 542 N when you stand on it.

f=ma 9.8N=5311.6/9.8=542ib

Give two (2) reasons alternative energy sources are needed.

fossil fuels are running out and energy demands are increasing

How does the frequency of a wave change when the wavelength decreases?

frequency increases

The type of matter that has no definite volume or shape and is made up of charged particles is a _______________.

gas

1. Water from deep in the Earth is turned to steam by magma; the steam rises and turns a turbine. As the water cools, it is sent back down into the Earth to recharge the system. What type of power is this?

geothermal power plants

Explain the path of a projectile as it moves through the air. What causes this path?

gravity has a downward force so it causes the object to go downward.

1. What type of power plant is often built into dams on lakes and rivers?

hydroelectric power plant

What type of electromagnetic wave is known as heatwaves?

infrared radiation

1. What is a hydrogen fuel cell?

is a device that converts chemical potential energy (energy stored in molecular bonds) into electrical energy.

1. In general the longer the wavelength, the larger the detector must be. If you met an aliens from a planet and they saw mainly by infrared light... a. Would you expect their eyes to be larger or smaller than our own?b. EXPLAIN why you selected the answer you did.

larger. the infrared lights are greater in space

Are AM wave frequencies higher or lower than FM frequencies? (circle one)

lower

Name the correct metric base unit for each of the following measurements. Mass, Weight, Density, Volume, Length, Temperature

mass: grams weight:newtons density: kg/cm 3 volume: liter length: meter temp: kelvin

Which type of wave, mechanical or electromagnetic must have a medium through which to transport energy? Circle the correct choice.

mechanical

When television first started (in the 1950s) what type of electromagnetic wave was used to transmit signals?

microwaves

What are the three types of nonrenewable energy sources we talked about in class?

natural gas, coal, petroluem

1. What is a major problem with using nuclear fission as an energy source?

neutron radiation damage and radioactive waste

1. What type of power plant uses enriched Uranium-238 as its fuel source?

nuclear reactors

EXPLAIN the difference between opaque, translucent and transparent.

opaque-not able to be seen through; not transparent. translucent -(of a substance) allowing light, but not detailed shapes, to pass through; semi-transparent transparent-(of a material or article) allowing light to pass through so that objects behind can be distinctly seen.

What is the equation for calculating the momentum of an object?

p=m(v)

The inside surface of the glass inside a vacuum bottle (thermal cup or thermos) is coated with aluminum to prevent heat loss by _______________________________________________. The vacuum created between the inside and outside layer of the bottle prevents heat loss through __________________ and __________________ because ____________________________________________________________________ .

radiation, flasks, thermos, prevents heat loss by conduction

List the 7 types of electromagnetic waves from lowest frequency to highest frequency. Label which wave has the shortest wavelength and which wave has the longest wavelength.

radio,tv,micro,infrared,UV,XRays,gamma gamma-shortest radio-longest

Does red or violet light have a longer wavelength?

red

What occurs when a wave strikes an object and bounces off?

reflaction

What is the equation for calculating the speed of an object?

s=d/t (speed=distance/time)

A high-speed train travels with an average speed of 227 km/h. The train travels for 2 h. What is the distance the train traveled?

s=d/t 227km/h=d/2h d=454km

A cross-country runner runs 10 km in 40 minutes. What is his average speed?

s=d/t s=10km/40m s=0.25km/m

what is the scientific law? what is the scientific theory?

scientific law-a statement about what happens in nature and that seems to be true all the time scientific theory- An organized set of investigation procedures

1. Rank these energy sources in order starting with the one that we use from greatest to least: hydroelectric, wind, fossil fuels, nuclear, solar

solar, wind, fossil fuels,hydro electric, nuclear

Describe the motion of particles in a solid compared to a liquid or gas.

solid particles are packed tightly together. liquid they flow freely

Through what phase of matter is convection least likely to occur? Why?

solids. the solid partials are not fluid

What happens to the speed of electromagnetic waves when they travel from water to air?

speed goes slow with fast

Acceleration occurs when an object changes its _____________ or _______________.

speed or direction

What does the Law of Reflection state?

states that the incident ray, the reflected ray, and the normal to the surface of the mirror all lie in the same plane.

What does Newton's First Law of Motion state?

that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force

DESCRIBE an example of diffraction.

the closely spaced tracks on a CD or DVD act as a diffraction grating to form the familiar rainbow pattern seen when looking at a disc

1. When you look at an object why do we see that particular color? (for example, why are the leaves green?)

the color that wee see is being reflected back to our eyes and all the other colors are being absorbed into the object

1. Choose one RENEWABLE fuel source (__________ ___) that we discussed in class.a. DESCRIBE two advantages to using that fuel source.b. DESCRIBE two disadvantages to using that fuel source.

wind. its clean fuel source. it doesn't pollute. there's no wind, no producing energy. wind turbines can disturb birds

How many meters are in 20.8 millimeters?

0.0208 m

1. On what multiple is the SI system based on?

10s

What is the frequency of the ocean wave if the wavelength is 12m and the velocity is 36m/s?

36m/s=f•12m= 3Hz

How many millimeters are in 8.31 kilometers?

8310000 ml

1. What type of power plant requires hundreds of devices, is only 20% efficient, and cannot be used all the time?

cooling power plants

what is the formula used to find the density of an object?

density=mass/volume

What electromagnetic wave is used for magnetic resonance imaging of the human body?

V-Ray

What does Newton's Second Law of Motion state?

any two masses exert an attractive force on each other

What three ways can be used to gather scientific information?

Observations, Form a hypothesis and Test the hypothesis

1. You are going to wrap your hot-water heater with insulation to prevent heat from escaping into air. a. Would you want to place the insulation close to the tank or away from the tank?b. EXPLAIN why you selected the answer you did.

away because air is a good insulator

If you have a slinky, describe how you would make a compressional wave and a transverse wave.

compressional wave-Move your hand side to side transverse-sideways to the motion

EXPALIN the difference between conduction and convection.

conduction is the transfer of heat energy by direct contact. convection is by actual motion of matter

EXPLAIN is the difference between constructive interference and destructive interference.

constructive interference is when the crest or the troughs of a wave interferes with the other destructive interference is when a crest and trough interfere with each other

How many kilograms are in 20 grams?

0.02 km

The average human body temperature is 98.6 oF. Calculate the temperature in oC.

C=5/9(F-32) C=5/9(98.6oF-32) C=5/9•66 C=36.6666... C=37oC

Which greenhouse gas is released when fossil fuels are burned?

CO2

1. What type of power uses photons of light to create a current of electrons between two metals?

Electromatic force

1. You are riding your bike past an ambulance when a siren goes off. a. DESCRIBE how the wavelength, pitch, frequency, and loudness changes as you ride toward the siren.b. What is the NAME of the scientific principle that you are describing?

First, the sound increases in loudness as the ambulance approaches and decreases in loudness as it moves away, which is expected. But in addition, the high-pitched siren shifts dramatically to a lower-pitched sound. As the ambulance passes, the frequency of the sound heard by a stationary observer changes from a constant high frequency to a constant lower frequency, even though the siren is producing a constant source frequency. The closer the ambulance brushes by, the more abrupt the shift. Also, the faster the ambulance moves, the greater the shift.

What does Newton's Third Law of Motion state?

For every action there is an equal and opposite reaction

1. You weigh yourself at the top of a high mountain and the scale reads 707 Newtons. a. **If your mass is 81 kg, calculate the acceleration due to gravity at your location. SHOW ALL OF YOUR WORK. a. EXPLAIN why this is not the same as the accepted value for acceleration due to the gravity of 9.8 m/s2.

Weight = (mass)x(accelerate of gravity). w=81•707=57267 because your on top of a mountain and the density is different

explain the difference between precision and accuracy.

When you are accurate, you look for the exactness of measurement. When you are precise you are exactly on the measurement.

Find the acceleration of a car that goes from 32 m/s to 96 m/s in 8.0s (use the formula for calculating acceleration).

a=64m/m/8.0s a=8m/s2

What is the formula for calculating acceleration?

a=force/mass

1. EXPLAIN the difference between a scientific law and scientific theory. a. In addition, provide ONE example of each.

the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory. It is a misconception that theories turn into laws with enough research. scientific law-suppose that you were lying under an apple tree and observed an apple fall from a branch to the ground. The observation of this phenomenon can be called the law of gravity. scientific theory- experiment a hypothesis

Define wavelength.

the distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave

What happens to the force of gravity as two objects get further away from each other? What about as they get closer to each other?

the gravitational force decreases when pulled away. when closer it increases

Define amplitude.

the maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Define intensity.

the measurable amount of a property, such as force, brightness, or a magnetic field.

Define frequency.

the rate at which something occurs or is repeated over a particular period of time or in a given sample.

DESCRIBE an example of refraction.

the sun's rays as they enter raindrops, forming a rainbow.

Which type of energy transfer doesn't require matter? Give one example of this happening.

thermal energy. radiation.

A material that reduces the flow of heat by conduction, convection, and radiation is _______.

thermal insolators

Are electromagnetic waves transverse or compressional waves?

transverse

What type of electromagnetic wave helps our bodies make vitamin D?

ultraviolet

If it is 55oC outside, how fast will a sound wave travel in that temperature? Use the formula V = (331) + (0.6 x T)

v=364

What is the formula to calculate the speed of a wave?

v=fλ

An ocean wave has a frequency of 20.0Hz with a wavelength of 10m. What is the velocity of the wave?

v=fλ 20.0Hz•10m=200m/s

how do you find the volume of an object with an irregular shape?

water displacement method

what is weight? how is weight different from mass?

weight is the measure of the pull of gravity. weight has to do with the measure of pull of gravity and mass has to do with the measure of matter in an object.

An experiment was designed to investigate the effect of caffeine on the heartbeat of shrimp. Two populations of shrimp were cultured. Both populations had water with the same mineral content, were supplied with identical amounts of small shellfish as food, received the same amount of light, and had their temperature maintained at 20ºC. Every two hours, shrimp from both populations were selected and their heartbeats were monitored. The shrimp of population one had caffeine administered five minutes before their heartbeat was checked. The shrimp of population two were given nothing. A= independent variable B= dependant variable C= constant D= control group E= experimental group

what part of the experimental was the food? C what was the heartbeat? B what was the water temp? E population 2? D the caffeine? A

What creates electromagnetic waves?

when an electric field couples with a magnetic field

1. What type of power uses a turbine built with long slender blades to produce electricity?

wind power