Chapter 19.1 - 19.4; Electric Potential Energy

Tophat reading 2

Are energy and voltage the same thing?

No

As an object is moved away from earth, does the gravitational potential energy increase or decrease?

Gravitational potential energy increases

• As distances increases, the gravitational potential energy increaeses

As a positively charged onject is moved away from an object with a negative charged, does the Electric potential energy increase or decrease?

Electric Potential Energy increases

• as distances increases, electric potential energy increases

Electric potential energy decreases when?

When the positive object is moved near the negatively charged object

When a free positive charge (q) is accelerated by an electric field, what happens?

It is given kinetic energy

Potential Energy (PE) uses which unit?

Joules (J)

Work done by a conservative force is the __________ of the ____________

• negative

• Change in potential energy

W = -deltaPE

Work (W) done to accelerate a positive charge from rest is positive or negative?

Positive because…

There is a loss of Potential Enegy which is ( —deltaPE meaning negative change in Potenital energy)

Negative change in potential energy (—deltaPE) means what?

The work is positive meaning there is acceleration

W=Fd*cos*the angle

What is the variable used for electric potential ?

V

What is the electric potential energy per unit charge?

V=PE/q

delta V is equal to the potential energy of a charge q at the final position (b) minus the potential energy of a charge q at the initial position (a)

DeltaV = Vb - Va = deltaPE/q (change in potential energy over q)

How many joules per coulomb is 1 V (voltage)?

1 J/C

*they are equal; 1V = 1 J/C

Define voltage

• the potential difference between two points

• The energy per unit charge

Example: every battery has two terminals and its voltage is the potential difference between them. Additionally, yet one stores much more energy than the other since

deltaPE = q deltas