Register to reply 
[Problem]: Magnitude/direction of magnetic force, electric force and the net force. 
Share this thread: 
#1
Nov2409, 03:01 PM

P: 3

1. The problem statement, all variables and given/known data
A magnet produces a 0.40 T field between its poles, directed horizontally to the east. A dust particle with charge q = 8.0×10^18 C is moving vertically downwards with a speed of 0.30 cm/s in this field. Whilst it is in the magnetic field, the dust particle is also in an electric field of strength 1.00×10^2 V/m pointing to the north. (a) What is the magnitude and direction of the magnetic force on the dust particle? (b) What is the magnitude and direction of the electric force on the dust particle? (c) What is the magnitude of the net force on the dust particle? 2. Relevant equations F=qvB F=(kq1q2) / r^2 B=E/V 3. The attempt at a solution a) Magnitude: F=qvB = (8 x 10^18 C)(0.003 m/s)(0.4 T) = 9.6 x 10^21 N Direction: Since the velocity is south and the force must be perpendicular to the velocity, the force must lie in a plane perpendicular to the north/south axis. b) I know it has to do with "1.00 x 10^2 V/m" but all I could do with it was: Magnitude: B=E/V > (1.00 x 10^2 V/m) / (0.003 m/s) = 3.3(repeating) T Direction: North c) Would the net force be the sum of answers "a" and "b" or would it be: Net force = sqrt(a^2 + b^2) a: being the force in a) b: being the force in b) Thankyou. 


#2
Nov2509, 02:38 AM

HW Helper
P: 2,249

Hi quik,



#3
Nov2509, 02:56 PM

P: 3

Hello alphysicist, thanks for replying.
+z axis = out of screen +x axis = B y axis = v But if the force is either North or South, since the velocity is going south, wouldn't it be north? Thanks again 


#4
Nov2509, 07:13 PM

HW Helper
P: 2,249

[Problem]: Magnitude/direction of magnetic force, electric force and the net force.



#5
Nov2709, 01:10 AM

P: 3

Direction: North Direction: South Magnitude: 7.04 x 10^20 N Direction: South 


#6
Nov2709, 12:50 PM

HW Helper
P: 2,249




Register to reply 
Related Discussions  
Magnitude and Direction Force Problem  Introductory Physics Homework  13  
Lorentz Force Law to determine the magnitude and direction of an electric field  Introductory Physics Homework  10  
Magnitude and direction of electric force (file attached)  Introductory Physics Homework  6  
Magnitude of an electric force problem with vectors  Introductory Physics Homework  3  
Magnetic Force to balance out Electric Force  Introductory Physics Homework  2 