click below
click below
Normal Size Small Size show me how
PS_Test#3
Question | Answer |
---|---|
According to the definiton of mechanical work, pushing on a rock accomplishes no work unless there is | movement in the same direction as the direction of the force |
The metric unit of a joule (J) is a unit of | any of the above (potential energy, work, kinetic energy) |
A Nm/s is a unit of | power |
A kilowatt-hour is a unit of | work |
A power rating of 550ft *lb per s is known as a | horsepower |
A power rating of 1 joule per s is known as | watt |
According to PE=mgh, gravitational ptential energy is the same thing as | work against a vertical change of position |
Two cars have the same mass, but one is moving three imes as fast as the other is. How much more work will be needed to stop the faster car? | Nine times as much |
Kinetic energy can be measured in terms of | both a&b (work done on an object to put into motion & work done on a moving object to bring it to rest) |
Potential and kinetic energy are created when work is done to change a position (PE) or a state of motion (KE). Ignoring friction, how does the amount of work done to make the change compare to the amount of PE or KE created? | Both are the same |
Many forms of energy in use today can be traced back to | the Sun |
In all of our energy uses, we find that | the total amount of energy is constant in all situations |
Any form of energy can be converted to another, but energy used on Earth usually ends up in what form? | Radiant |
Radiant energy can be converted to electrical energy using | solar cells |
The "barrel of oil" mentioned in disxussions bout petroleum is | 42 U.S. gallons |
The amount of energy generated by hydroelectric plants in the U.S. as part of the total electrical energy is | decreasing because new damns are not being constructed |
Fossil fuels provide what percent of the total energy consumed in the U.S. today? | 86 percent |
Alternatice sources of energy include | all of the above (solar cells, wind, hydrogen) |
A renewable energy source is | biomass |
The potential energy of a box on a shelf, relative to the floor, is a measure of | all of the above (the work that was required to put the box on the shelf from the floor, the weight of the box times the distance above the floor, the energy the box has because of its postion above the floor |
A rock on the ground is considered to have zero potential energy. In the bottom of a well, the rock would be considered to have | negative potential energy |
Which quantity has the greatest influence on the amount of kinetic energy that a large truck has while moving down the highway? | Velocity |
Electrical energy can be converted to | any of the above (chemical, mechanical, radiant energy) |
Most of all energy comes to and leaves Earth in the form of | radiant energy |
A spring-loaded paper clamp exerts a force of 2N on 10 sheets of paper it is holding tightly together. Is the clamp doing work as it holds the papers together? | No |
The force exerted when doing work by lifting a book bag agaisnt gravity is measured in units of | N (Newtons) |
An iron cannonball and a bowling ball are dropped at the same time from the top of a building. At the instant before the balls hit the sidewalk, the heavier cannonball has a greater | kinetic energy |
Two students are poised to dive off equal-height diving towers into a swimming pool below. Student B is twice as massive as student A. Which of the following is true? | Student B did twice as much work climbing the tower |
A car is moving straight down a highway. What factor has the greatest influence on how much work must be done on the car to bring it to a complete stop? | How fast it is moving |
When you do work on something, you give it energy | every time |
Which of the following is not the use of a solar energy technology? | Water from a geothermal spring |
Today, the basic problem with using soalr cells as a major source of electricity is | manufacturing cost |
The solar technology that makes more economic sense today than the other applications is | water heating |
Petroleum is believed to have formed over time from buried | organic sediments |
Two identical cars are moving stright down a highway under identical conditions, except car B is moving three times as fast as Car A. How much more work is needed to stop car B? | Nine times as much |
The work accomplished by lifting an object against gravity is measured in units of | J (Joule) |