# Elements of electromagnetics

$F =q*(E+v times B)$ where $F$, $E$, $v$ and $B$ are vectors and $times$ is the vector product.

$F =q*[4*i + (10*j) times (5k)] = 4*i +50*i =54*i$ N

$F=m*a$

$a =54*i m/s^2$

$v =a*t +u0= 54*i+10*j$ m/s after $t =1 sec$

$s =at^2/2 +s0= 54*i/2+0 =27*i$ m

$E_k =m v^2/2 =1/2*(54*54+10*10) =1508 J$

7.

$F = q*E = 4i N$

$a =F/m = 4i$ m/s

$v = at+u0 =4i+10j m/s after t=1 sec$

$s = at^2/2=4*i/2*1^2 =2*i$ m

$E_k = m v^2/2 =1/2*(4*4+10*10) =58 J$

8.

$F=q(v times B) = 0$ because $u0=0$

$a =0 m/s^2$

$v =u0+at =0 m/s$

$s =0 m$

$E_k =0$