Answer:
[tex]F=1.143*10^{-3}N[/tex] and [tex]q=3.24*10^{-5}c[/tex]
Explanation:
a) We need first to identify the Period from the one-quarte 'time' given. That is
[tex]t=6.4*10^{-3}s[/tex]
Then the period is,
[tex]T=4t=4(6.4*10^{-3})=25.6*10^{-3}[/tex]
From this Period we can calculate the radio,
[tex]v=\frac{2\pi r}{T}[/tex]
Rearrange for r,
[tex]r=\frac{vT}{2\pi}\\r=\frac{(75m/s)(25.6*10^{-3}s)}{2\pi}\\r=0.305m[/tex]
We know can calculate the Magnetic force,
[tex]F=\frac{mv^2}{r}=\frac{(6.2*10^{-8})(75)^2}{0.305}\\F=1.143*10^{-3}N[/tex]
b) To find the charge we only use the Force in terms of the electric field, that is
[tex]F=Bvq[/tex]
Rearrange to q,
[tex]q=\frac{F}{Bv}\\q=\frac{1.143*10^{-3}}{(0.47)(75)}\\q=3.24*10^{-5}c[/tex]