11-71. A particular proton in space is subjected to two fields: a
gravitational field (1.30X105 N/kg toward planet X),
and
an electric field (2.47X10-4 N/C away from planet X).
(a) If the proton is released from rest, in which direction will
it move?
(b) After moving 1.50 m, what will be its speed? Use energy
methods
and assume uniform fields.
ACCUMULATED SOLUTION
FE = qE
Fg = mg
Fg = mg
= (1.673X10-27 )(1.3X105) = 2.175X10-22
N
FE = qE = (1.602X10-19
)(2.47X10-4) = 3.957X10-23 N
No. The gravitational force is doing work against the electric field.
(In the absence of gravity the charge would move the other way.) Does
the
electrical PE increase or decrease?
Click on the correct answer