The First Law of Thermodynamics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Mechanical Work

A

Mechanical Work is energy that is transferred to an object which causes it to move. You know work has been done if it changes position, or changes shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Conservation of energy

A

Energy is always conserved - energy can be added or removed from a system but never lost. Energy is added or removed, or transferred to or from the system by mechanical work.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The first law of thermodynamics I

A

Delta U = Q + W

Q = +ve if heat is added
Q = -ve is net heat is removed
W = +ve if net work is done on the system
W = -ve is negative if net work is done by system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The first law of thermodynamics II

A

Internal energy of an object increases if heat (Q) is added. Internal energy of an object increases if work (W) is done on the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Heat Loss in Mechanical Systems

A

In physics, we often talk about perfect system but in real life these don’t exist. In the real world, some heat will be lost to the surrounding environment. This means that the actual usable energy is less than the amount we calculate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly