Confusion on applying right hand rule

[Genericcoder]

Hi guys I always get confused when I do the right hand rule like here when I apply it to this problem I am getting different answer than what the book have.

A uniform magnetic field B, with magnitude 1.2 mT, points vertically upward throughout the volume of the room in which you are sitting. A proton with kinetic energy of 5.3 MeV moves horizontally to the north through a certain point in the room. What magnetic deflecting force acts on the proton as it passes through this point ? The proton mass is 1.67 * 10^-27 kg.

so Fb = 6.1 * 10^-15 N; the book then says the force is sideways in horzontally to the east. I am getting it pointing in the z direction even when using cross product

FB = q<v,0,0> x <0,B,0>

Fb = qvB k^ direction

 

[Nugatory]

What's your convention for relating north/south, east/west, and up/down to the x, y, and z axes? You know you've mixed something up if the force isn't perpendicular to the B field and the velocity.

(I'm assuming that you are using i,, j, and k as unit vectors in the x, y, and z directions respectively).

 

[Genericcoder]

Ye I am using i j k as unit vectros x,y,and z directions respectively.. but I think that's what I have not relating north/south up down to x and y and z directions..

 

[dauto]

Shouldn't your field be (0,0,B)?

 

[Nickie]

First of all, it is important to note that the right hand rule is a tool used to determine the direction of the magnetic force on a charged particle moving through a magnetic field. It is based on the cross product of the velocity of the particle and the magnetic field vector. It is a common source of confusion, so do not worry if you are struggling with it.

In this specific problem, we have a uniform magnetic field B pointing vertically upward and a proton moving horizontally to the north. To apply the right hand rule, you need to align your thumb with the velocity vector (north) and your fingers with the magnetic field vector (up). The direction in which your palm is facing will be the direction of the magnetic force.

In this case, your thumb will be pointing to the east and your palm will be facing upward, indicating that the magnetic force is sideways and horizontally to the east, as the book states.

It is important to note that the direction of the magnetic force on a charged particle depends on both the direction of the magnetic field and the direction of the particle's velocity. So, if you change the direction of either one, the direction of the force will also change.

To summarize, make sure you are correctly aligning your hand with the velocity and magnetic field vectors, and remember that the direction of the force depends on both of these vectors. Keep practicing and don't hesitate to seek help if you are still struggling with the right hand rule. It is a valuable tool in understanding and analyzing magnetic fields and their effects on charged particles.