I. _________ explain forces ______________________________.All fields are ___________ because they have ____________ .

A. ___________________field

Earth

Measure the force of gravity Fg acting on a test __________.

Fg

m

magnitude:gravitational field _________ g = Fg / m

direction: __________________same as Fg

Near Earth’s surface:

that act at a distanceFields

mass mGravitational

Same as _____________________due to gravity _______________

g = -9.81 N/kg

the acceleration

strength

vectors direction

= -9.81 m/s2

B. _____________ field:

Fe

q

magnitude:

electric field _______________ E = Fe / q

direction: same as Fe

_________object

Measure the electric force Fe acting on a

_____________________________.

Electric

positive test charge q.

charged

strength

test _________

direction: Same as the direction that the __________ __________of the test compass points when the compass is placed in the _______

magnet

C. ________________ field:

magnitude:magnetic field ______________ =

Magnetic

compass

stronger near magnetstrength

northpole

field

The equation formagnetic field strengthis complicated andwill not be used inthis course.

NS

1. Any field force is ___________________to its field lines.

F1F2F3

12

3

tangent

Notes on fields:

field line

A ____________ compass is really a ___________________that is _________________ on a _________________ pin.

magnetic tiny magnetbalanced low-friction

_____

___________

S N

magnet

pin

3. Why do field lines never cross?

2. In the diagram below, where is the field strongest?

A B

At ____ , because

the _____________

the lines, the

____________ the

field.

field line 1

field line 2

F2

F1

PAt point P, therewould be _____ ___________ forces.

B

stronger

closer

2different

??

_______________________ of the different fields:

type of field

testobject

direction of the fieldis the same as thedirection of the….

gravitational mass

mgravitational force acting on m

electricpositivecharge

q

electric force acting on the “+” q

magneticmagneticcompass

north pole of the compass

Comparison