Formula for kinetic energy of an object:
KE = 0.5mv²
m is the mass and v is the velocity.
Formula for the work done on a charged object by moving it through a potential difference:
W = ΔVq
ΔV is the potential difference and q is the charge of the object.
To find the potential difference needed to decelerate an electron to rest, set the work done on the electron equal to its kinetic energy:
W = KE
Substitute W = ΔVq and KE = 0.5mv²
ΔVq = 0.5mv²
Given values:
q = 1.6×10⁻¹⁹C
m = 9.11×10⁻³¹kg
v = 6.0m/s
Plug in the given values and solve for ΔV
ΔV×1.6×10⁻¹⁹ = 0.5×9.11×10⁻³¹×6.0²
ΔV = 1.02×10⁻¹⁰V
