# Magnetic forces and Magnetic fields Homework (in need of help ASAP)

#### gwendalagan

hi!
I really need help in solving this problem. i do not know hot to get the y and z components of the magnetic field vector. who can help me please?
A 2.5 nC particle of mass 5.25x10^-6 kg moves through a uniform magnetic field of 7.5 T directed down at 30 degrees in the y-z plane. find the force on the particle at the instant its velocity is 8.0x10^4 m/s along the y axis.

#### topsquark

Forum Staff
hi!
I really need help in solving this problem. i do not know hot to get the y and z components of the magnetic field vector. who can help me please?
A 2.5 nC particle of mass 5.25x10^-6 kg moves through a uniform magnetic field of 7.5 T directed down at 30 degrees in the y-z plane. find the force on the particle at the instant its velocity is 8.0x10^4 m/s along the y axis.
B is directed downward (aka in the negative z direction) at an angle of 30 degrees below the +y, so $$\displaystyle B_y = B ~ cos(30)$$ and $$\displaystyle B_z = - B ~ sin(30)$$.

If it helps you to visualize it recast this into the form that the field is 30 degrees below the +x axis. Then $$\displaystyle B_x = B ~ cos(30)$$ and $$\displaystyle B_y = - B ~ cos(30)$$.

-Dan

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