Answer:
[tex]2.4\cdot 10^{-11} N[/tex]
Explanation:
Since the Earth's magnetic field is perpendicular to your direction of motion, the strength of the magnetic force exerted on your head is given by:
[tex]F=qvB[/tex]
where:
[tex]q=6\cdot 10^{-9}C[/tex] is the charge on your head
[tex]v=80 m/s[/tex] is the speed at which you are moving
[tex]B=5\cdot 10^{-5} T[/tex] is the strength of the magnetic field of the Earth
By substituting these numbers into the equation, we find the strength of the magnetic force:
[tex]F=(6\cdot 10^{-9}C)(80 m/s)(5\cdot 10^{-5} T)=2.4\cdot 10^{-11} N[/tex]