Instead of the electron in above example , suppose a proton ( `m = 1.67 xx 10^(-27)kg)` was accelerated from rest by a potential difference `V_(ba) = -5000V`. What would be the proton's
(1) Change in PE ? (2) Final speed ?

Explanation

(a) `DeltaU = - 5000 eV`
`= - 5000 xx 1.6 xx 10^(-10 )J`
`= - 8.0 xx 10^(-16) J`
(b) `DeltaK =K-0= (1)/(2) mv^(2) = 8 xx 10^(-16) J`
`implies v sqrt((2 xx 8 xx 10^(-16))/( 1.67 xx 10^(-27)) )= sqrt((1.60 )/( a1.67) xx 10)`
`= 9.8 xx 10^(5) m //s`