Chapter 11 Work, Power, Energy
Two times as much
To do twice as much work in the same amount of time, how much power is required?
the mass of the object and the velocity of the object squared
To which of the following variables is kinetic energy proportional?
That for any system the total amount of energy remains the same
What does the law of conservation of energy state?
Newton-meter.
What is a joule?
Any situation where outside forces are not acting
What is a system?
The transfer of thermal energy from one object or system to another.
What is heat?
approximate the area under a curved line is to break it up into rectangles.
What is rectangular approximation?
Watt
What is the standard unit of power?
Convection
What is the term that describes the fluid motion of hot air rising or cool air sinking?
The movement of particles.
What makes thermal energy possible?
The surface of the Earth would cool.
What would happen if geothermal energy ceased to exist?
energy lost
When energy is transformed from one form to another, or moved from one place to another, or from one system to another there is energy loss.
force applied times distance moved
Which best describes 'work?'
Any force that is not constant
Which best describes a variable force?
Work done is equal to the change in energy
Which best describes the work-energy theorem?
Applying a force to an object
Which does not constitute a change in energy?
The velocity of the object
Which is NOT a component of work done on an object?
It only applies to an increase in energy
Which of the following is NOT true about the work-energy theorem?
joules
Which of the following is a common unit that is used to measure energy?
A bike rolling down a hill
Which of the following is an example of kinetic mechanical energy?
A rolling bowling ball.
Which of the following is an example of mechanical energy?
A bottle of sugar sitting on the counter top
Which of the following is an example of potential energy and not kinetic energy?
A mouse tripping a mouse trap
Which of the following is an example of potential energy transformed into kinetic energy?
a book raised above your head
Which of the following is an example of potential mechanical energy?
The capacity to do work.
Which of the following is the best definition for energy?
the ability to do work
Which of the following is the best definition of energy?
Energy possessed by an object due to its location or motion
Which of the following is the best definition of mechanical energy?
Energy from a natural resource that can be replenished.
Which of the following is the best definition of renewable energy?
More work, less time
Which of the following scenarios will most likely require MORE power?
Work / time
Which of the following scenarios will most likely require MORE power?
Thermal energy
Which of the following types of energy does the sun use to heat up our atmosphere?
Radiation always causes illness.
Which statement is NOT true about all forms of radiation?
It completely stops the transfer of heat.
Which statement is NOT true about insulation?
The fast car has more kinetic energy
Why does it take more work to stop a fast car than a slow one?
The air is a poor conductor of heat.
Why is it possible to reach your hand into the oven without injury, but harmful to touch the pan inside it?
Potential energy is known as stored energy because there is the potential to do work.
Why is potential energy called stored energy?
If outside forces such as friction do act on the system, energy may be lost as heat.
Why would a system have less energy than it originally started with?
Potential
A bike resting at the top of a hill would be an example of what type of energy?
none
In the absence of friction, how much energy would be lost as a rollercoaster car goes down the first of several 'hills'?
the amount of work is doubled
If you double the force on an object but the distance remains the same, how much work is done on that object?
yes
Can Different types of energy can be categorized as either kinetic or potential.
At the top of the swing
Consider a ball at the end of a string. If the ball is swinging back and forth, at what point in the swing would the ball have the most potential energy?
10 W
How much power is required to do 100 J of work in 10 s?
Since the object is not being moved, there is no work done.
How much work is done when you hold a 10 N object 10 m above the ground?
The Earth's core.
Most of the Earth's geothermal energy is contained within:
The work done
On a graph where force is on the y axis, and distance is on the x axis, a curve is applied to show the force and distance of a moved object. What does the area under the curve represent?
The oven circulates hot air which cooks the food.
The oven in your house uses convection to heat food. This means that _____.
