Term
| Why does placing wheels under a heavy box reduce the necessary force require to push it along at a constant speed? |
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Definition
| The wheels allow the load to be equally distributed and moves the force on movement onto something that rolls reducing the required force |
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Term
| identify the 4 fundamental forces in natture |
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Definition
Strong Nuclear Power
Weak NP
Elcromagnetic
Gravity |
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Term
| What happens whenever a net force acts on an object? |
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Definition
| All of the forces form together |
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Term
| Identify the type of enregy stored in a stretched bungee cord. |
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Definition
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Term
| explaon how the sunlight converted into potential energ by plants |
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Definition
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Term
| Explain how the kinetic energy of am object changes when the speed of the object doubles |
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Definition
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Term
| Contrast chemical energy with mechanical energy. |
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Definition
| chemical energy is when the energy that is released when a chemical compound reacts to produce new compounds. A mechanical energy is the sum of the kinetic and potential energy of large-scale objects in a system. |
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Term
| Explain why free-fall acceleration can be regarded as constant for objects falling within a few hundered miles of Earth's Surface. |
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Definition
| Since the radius of Earth is far greater(rough: 6400km) than a few 100m, you can neglect that distance and still have g=9.80 |
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Term
| Apply Newtonn's third law of motion to explain how 2 billiard balls, moving toward each other at the same speed, collide and move away from each other at the same speed as before. |
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Definition
| The action of them hitting each other is = by them bouncing. They would move in the opposite direction. |
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Term
| apply the concept of momentum to compare the mass and velocity of a slowmoving train and a hih-speed bullet |
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Definition
| The train has a larger mass |
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Term
| Infer what you can say about the velocity of a car that is moving with a constant momentum.? |
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Definition
| the car is moving at constant velocity. |
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Term
| Apply Newtpn's first and secong laws to explain why an object moving in a circular path at a constant speed is undergoing acceleration and has a force exerted on it. |
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Definition
| When the object is moving in a circular path, applying Newton's first law of motion, there is no outside or unbalanced force exerted upon the object, so it stays in constant motion. The force that is being exerted upon it is balanced and so it the mass times acceleration is the same as the force, so it stays in constant acceleration and at a constant speed as it goes on the same circular path. |
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Term
| Explain why a bacward-facing car seat is safer for an infant than a forward-facing car seat during a collision or abrupt stop. |
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Definition
| The baby would not slide forard, the cack af the seat safely distributes the force pushing him fwd. |
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Term
| Use the concept of inertia to illustrate why volleyball is not played with a ball that hass mass similar to a bowling ball? |
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Definition
| The Action Force of the ball would be greater than the reaction force of your hands trying to hit it. This could cause you to break a finger... |
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Term
| explain the relationship between work and power |
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Definition
| Power is the rate of doing work |
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Term
| Can you Explain how machines make work easier if they still require that same amount of work be done? |
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Definition
| Machines make work easier by allowing you to use less force over a greater distance to get a task accomplished |
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Term
| List two ways mechanical energy can be transfomed to nonmechanical energy |
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Definition
•Moving an object across another can result in heat through friction. This is conversion of the mechanical energy into thermal energy.
•In an electric motor, the (mechanical) rotation of the coils results in electrical current and therefore electrical energy. |
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Term
| Describe why a high-efficiency machine is more desirable thana low-efficiency machine? |
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Definition
| "High efficiency" means that a large percentage of the energy used by the machine is converted into the desired output. |
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Term
"High efficiency" means that a large percentage of the energy used by the machine is converted into the desired output.
Read more: http://wiki.answers.com/Q/Describe_why_a_high-efficiency_machine_is_more_desirable_thana_low-efficiency_machine#ixzz1NDX8ifVR |
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Definition
Because energy is lost due to air resistance and through inelastic deformation of the ball with the ground when it bounces.
Read more: http://wiki.answers.com/Q/Explain_why_the_height_of_a_bouncing_ball_decreases_after_each_bounce#ixzz1NDXNSwtx |
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Term
| How does a skier gliding down a hill illustrate the conservation of energy |
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Definition
| When a skier goes down a hill, the skier slowly loses potential energy the farther down the hill he is. This causes the skier's kinetic energy to increase, as predicted by the law of conservation of energy |
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Term
| Why does a ceramic bowl keep oatmeal hot longer than a stainless steel bowl |
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Definition
| A ceramic bowl will keep oatmeal hot longer than a stainless steel bowl because the stainless steel conducts heat much better and the ceramic bowl if heated will hold its heat much longer than stainless steal |
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Term
| Explain which method of heat transfer can take place if 2 objects at different temp. are placed w/o touching each other in a vacuum |
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Definition
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Term
| Explain why steam (gas) has a lower specific heat than water (liquid).? |
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Definition
| molecular density of the gas is less than the liquid |
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Term
| Describe the method of heat transfer involved when you mix hot water with cold water to make lukewarm water. |
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Definition
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Term
| Determine which is the best type of skillet. Some people prefer a heavy cast iron skillet while others prefer a thin stainless steel one |
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Definition
Describe the method of heat transfer involved when you mix hot water with cold water to make lukewarm water
Read more: http://wiki. |
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Term
| Which of the 4 common types of nuclear radiation can be described as an uncharged particle. |
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Definition
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Term
| Why are gamma rays more dangerous than alpha paticles or beta |
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Definition
| Gamma rays can pass through many more materials, such as clothing or walls. tjan alpha or beta particles can. |
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Term
| describes what happens to the mass number and the atomic number of an atom during beta decay. |
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Definition
| During beta decay, a neutron in the nucleus decays to form a proton and an electron. Atomic # changes bc there is one more proton in the nucleus. Mass # does not chance bc the total number of protons and neutrons in the nucleus does not change. |
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Term
| Tell the process to describe how nuclear fission is used to produce electricity. |
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Definition
* Uranium-235 nuclei undergo a chain reaction.
* A collan absorbs energy from the chain reaction.
* Water absorbs energy from the coolant and changes tp steam.
* The steam turns a turbine attached to a generator.
* A generator changes the mechanical energy of the spinning turbine in2 electrical energy. |
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Term
| List 3 activities that add to an individual;s exposure to radiation. |
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Definition
| smoking, traveling in plane, and x-ray |
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Term
| How do smoke detectours use nuclear radiation to detect a fire. |
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Definition
| A radioactive element in the smoke detector . The alpha particles produce elecric curren when smoke itterrups the current |
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Term
| What two factors determine the risk of damage from nuclear radiations? |
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Definition
| type of radiation and the amt. of radiation exposure. |
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Term
| Why is it important to use low levels of nuclear radiation for detection of diseases? |
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Definition
| Low doses of radiation can have beneficial uses, but high lvls of nuclear radiation can cause radiation sickness. |
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Term
| What are 2 ways to reduce the lvls of radon gas in a building? |
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Definition
Install vent tah draw air out of a building.
Seal cracks in the foundation of a building. |
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Term
| What are two advantages and two disadvantages of using nuclear fission to generate electricity |
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Definition
Adv: Nuclear power does not produce gases that pollute the air; there is more energu in known uranium reserves than in known oil or gas reserves.
Dis.: Radioactive products of fission can release nuclear radiation into the environment; nuclear power plants are expensive to build. |
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Term
| list two living elements and two non living elements in the ecosystem of an ocean reef |
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Definition
| Two living elements of the reef are plankton and and algae. Two nonliving elements are rocks and sand. |
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Term
| explain how the word "interrelatedness" is a key to understanding the stability |
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Definition
| Humankind benefits from a multitude of resources and processes that are supplied by natural ecosystems. Collectively, these benefits are known as ecosystem services and include products like clean drinking water and processes such as the decomposition of wastes. |
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Term
| List two human activities that cause changes in ecosystems |
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Definition
| Clearing trees, and driving cars. |
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Term
| Can you discuss the importance of an informed public, in that all all citizens have a better understanding of how ecosystems work before they vote on the construction of dams, highways,malls,housing development,etc? |
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Definition
| Ecosystems have no particular size. An ecosystem can be as large as a desert or a lake or as small as a tree or a puddle. If you have a terrarium, that is an artificial ecosystem. The water, water temperature, plants, animals, air, light and soil all work together. |
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Term
| Name the energy transfer process plants use to convert the sun's energy into stored chemical energy, |
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Definition
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Term
| state where all fossil fuels come from, and give an example of the three phases. |
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Definition
They come from organic compounds.
Liquid:oil
Solid: Coal
Gas: natural gas |
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Term
| state a disadvantage of the use of nuclear power |
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Definition
| It would cost a lot to clean if a spillage occured. |
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Term
| State the 2 proccesses by which we obtain energy from the nucleus of an atom. |
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Definition
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Term
| What is used in present-dau nuclear power plants? |
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Definition
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Term
How can reusing rinse water from dishes and laundry can reduce the use of energy and cut down pollution?
In: Pollution [Edit categories] |
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Definition
| by reusing them you will be recycleing the water, and so you would be using less water |
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Term
| describe how the human activity of driving a car contributes to global warming |
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Definition
| it puts out pollution in the air and uses gas. requires the combustion of tremendous amounts of fossil fuels. |
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Term
| list three major contributors to water pollution |
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Definition
| human activities, fertilizers, and pesticides, differeny materials that are water pollutants |
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Term
| Describe the harmful effects of acid rain on streams and lakes and on soil. |
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Definition
Makes water acidic and causes organisms to die.
Make soil less fertile |
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Term
| Explain why contaminants in soil are hard to remove? |
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Definition
| because the are usually chemicals such a s oul and gasoline. |
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Term
| Define temp in terms of KE |
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Definition
| temp. is the measure of KE |
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Term
| Explain how a liquid thermometer measures temp. |
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Definition
| liquid collapses and expands |
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Term
| Why cant an objext never reach a temp of absolute 0 |
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Definition
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Term
| Why is a fan blade spinning at a constant speed constantly accelerating. |
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Definition
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Term
| How is a frame reference used to describe motion? |
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Definition
| Its a system 4 specifying the precise location of objects in space and time. |
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Term
| What is the differece b/ K friction and static friction? |
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Definition
| Static friction resists sliding motion, |
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Term
| What happens to an object when an unbalaced force acts on it |
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Definition
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Term
| a nonrenewavke energy resource formed from the remains of organisms that lived long ago; exanles include oil, coal, and natural gas. |
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Definition
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Term
| the energy produced by heat within the Earth |
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Definition
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Term
| a resource that forms at a rate that is much slower than the rate at which the resource is consumed |
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Definition
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Term
| a natural resource that can be replaced at the same rate at whic the resource was cosumed |
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Definition
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Term
| a gradual increase in avg. global temp. |
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Definition
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Term
| an undesirable change i the natural environment that is caused by the into of substances that are harmful to living organisms or by excessive wastes, heat, noise, or radiation. |
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Definition
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Term
| a kind of energy created by the physical movement or rotation, revolution etc of anything.Since most of the movements done and energy created are done by machines, |
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Definition
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Term
| The energy of a particle or system of particles derived from position, or condition, rather than motion. A raised weight, coiled spring, or charged battery has |
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Definition
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Term
| The energy possessed by a body because of its motion, equal to one half the mass of the body times the square of its speed. |
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Definition
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