Ratio Gravitaional Force & Fb

1. 1
5
6
A cosmic-ray proton approaches
Earth vertically at the equator,
where the horizontal component
of Earth’s magnetic field is
3.5 10 T. If the proton is
moving at 3.0 10 m/s, what
is the ratio of the m



agnetic
force to the gravitational force
on the proton?
Solution
MAGNETIC FORCE ON A MOVING CHARGED PARTICLE

2. 2

3. 3
Let be the Magnetic Force &
be the Gravitational Force,
then
(1)
(2)
where is the mass of the Proton
B
G
B
G p
p
F
F
F quB
F m g
m
   
   
19 6
5
27
2
18
9
27
2
9
2
Now,
(1.6 10 ) (3.0 10 )
(3.5 10 )
(1.67 10 )(9.8 )
16.8 10 . .
. .
1.03 10
.
16.37 10
1.03 10
. . . . .
( 1)
. . . .
B
G
m
X C X X X
s
F X T
m
F X kg
s
m
X C T
C T s
s X
kg m kg
X
s
X
C T s C kg s C A s
kg A s kg A s A s






 

   