ok I'm stuck here...(adsbygoogle = window.adsbygoogle || []).push({});

At a particular point in time, an electron is moving with a velocity of

v=(2.0*10^6 m/s)i + (3.0*10^6 m/s)j

in a constant magnetic field with strength

e=(0.030T)i - (0.15T)j

What is the magnitude of the magnetic force on the electron at that moment? this i found by taking the cross product and multiplying by charge of an electron 6.246e-14N

The electron moves into an area where an electric field is used to bring its velocity to zero in 4.5 X 10-2 seconds. At the moment when the velocity of the particle is zero, what is the magnitude of the magnetic force on the particle?

this is where I'm stuck... i thought that vf = vi + at would give me the acceleration which I could then multiply by the mass of an electron (F=ma)... which would give me F... I know I'm probably missing something elementary here

so I got the magnitude of acceleration by taking the squares of both components of velocity and than the square root... as in sqrt(i^2 + j^2) = v

which gave me 1.3e13 m/s

so then I got 0 m/s = 1.3e13 m/s + a (4.5e-2 s)

a=-2.888e14 m/s^2

F= (9.110e-31 kg)*(2.888e14 m/s^2)

F=2.632e-16 N

so what am i missing?? thanks :grumpy:

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# Homework Help: Magnetic Force on a Particle

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