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I'm currently studying maths at Uni and this year I have to do a compulsary mechanics module. For the record, I've not done physics for a long time and I'm having a lot of trouble with some questions! Here they are as printed on the sheet:

"The force acting on a particle of mass

*m*moving under the influence of a constant magnetic field

**B**is equal to

**v**x

**B**where

**v**is the velocity of the particle relative to the origin 0 of an inertial frame. Suppose that at time t = 0, r=0 and v = V.

Show that mv = r x B + mV"

it gets better

"Let

**i**,

**j**and

**k**be unit vectors in the direction of the axes of the inertial frame. In this case

**B**=

*B*

**k**and V = v1

**i**+ v2

**k**, show that the path of the particle is given by

**r**= (mv1)/B sin (Bt/m)

**i**+ (mv1)/B(cos(Bt/m) - 1)

**j**+ v2t

**k**

Describe carefully the path of the particle.

[if x(.) = cy + d and y(.)= -cx (c and d constants) then x(..) = -c^2x]"

( x(.) denotes first derivative.)

My lecturer is hopeless and I'm currently failing this course. I would be really grateful for any replies!

Thanks

Dave