Module 12 Flashcards
A man pushes a stalled car for 2 minutes. During the first 1.5 minutes, the car does not move, but for the last 0.5 minutes the man pushes even harder and succeeds in getting the car to move. Describe if and when work is being done.
Work is being done for the last 0.5 minutes
How does something have potential or kinetic energy?
Classify each of the following as having either potential or kinetic energy or both:
a. A Gold bar
b. Sunlight
c. An apple
d. A hurricane
All matter has potential energy Something that is moving has kinetic energy a. potential b. kinetic c. potential d. both
A chemist watches the temperature of a vat of liquid an notices that it increases over time. What can the chemist conclude from this observation?
It is gaining energy
If a hot object is totally insulated from the outside world (totally unable to interact with anything else), will its temperature ever be able to change?
No
What is experimental scatter?
It is made by data points that are a little above or below the accepted value.
Heat is added to 2 identical objects that are initially at the same temperature. If the first absorbs 50.0 cal and the second absorbs 50.0 J, which gets hotter?
What is the relation between cal and J?
The first
1 cal = 4.184 J
Some diet books say that an excellent way to lose weight is to drink ice-cold water. Why?
The body must warm up the water which requires energy (burning more calories)
A heating curve levels off at two places. Where and Why?
At the beginning and at the end of the curve.
The lower one is where the melting/freezing point is.
The higher one is where the boiling point is.
The specific heat of aluminum is roughly 2 times that of iron. Equal masses of aluminum and iron start out at room temperature. What is added to each mass at the same rate for the same amount of time. The iron’s temperature increased by 900 *C. What was the temperature increase of the aluminum?
450 *C
Why should a calorimeter always be made from an insulating material?
Because if energy escapes it means that the experiment will not be correct.
What is Energy?
It is the ability to do work
What is Work?
It is the force applied to an object times the distance that the object travels parallel to that force.
What is Heat?
It is energy that is transferred as a consequence of temperature differences.
What is the first law of thermodynamics?
It is: Energy cannot be created or destroyed. It can only change form.
What is Potential energy?
It is energy that is stored
