The kinetic energy of electron is equal to the static energy. What's the wavelength?

The kinetic energy of electron is equal to the static energy. What's the wavelength?

Ek = (m-m0)c^2 = m0 * c^2
m = m0 / sqrt(1-v^2/c^2)
Sqrt root, M0 static mass
From the above two formulas, v = sqrt3 / 2 * C
Momentum MV = sqrt3 m0c
Wavelength = H / P = H / MV = sqrt3h / (3m0c)

Relationship between kinetic energy and momentum
Can momentum change?
Does kinetic energy change and momentum change?
When momentum changes, speed must change?
Momentum change, combined with external force must do work on the object?
Why?

The first sentence is wrong, because momentum has a direction, such as V1 = 6m / s, V2 = - 6m / s, momentum changes, kinetic energy remains unchanged. The second sentence is right, because kinetic energy changes, velocity must change, so momentum must change. The third sentence is wrong, which is the same as the first sentence

Does a body with kinetic energy have momentum? Does a body with momentum have kinetic energy? Does momentum change? Does kinetic energy change?

Kinetic energy: 1 / 2mV ^ 2
Momentum MV
So with kinetic energy, V must not be zero and momentum must not be zero
And vice versa: a body with momentum must have kinetic energy
Momentum changes, kinetic energy does not necessarily change: because momentum P = MV, where V is the vector, momentum changes when the direction changes, while kinetic energy remains unchanged (for example, uniform circular motion: momentum changes all the time, kinetic energy remains unchanged)