// Set Damping for realistic movement
this.mf_Body.LinearDamping = 5f;
// Set movement speed and max speed.
this.mec_movementSpeed = FarseerConvertUnits.ToSimUnits(new Vector2(10, 10));
this.mec_maxSpeed = FarseerConvertUnits.ToSimUnits(new Vector2(50, 50));

// Example movement code
public void IncreaseSpeedX()
{
    this.mf_Body.ApplyLinearImpulse(new Vector2(this.mec_movementSpeed.X, 0));
    this.mf_Body.LinearVelocity = new Vector2(Math.Min(this.mf_Body.LinearVelocity.X, this.mec_maxSpeed.X),
                                              this.mf_Body.LinearVelocity.Y);
}

public void IncreaseSpeedY()
{
    this.mf_Body.ApplyLinearImpulse(new Vector2(0, -this.mec_movementSpeed.Y));
    this.mf_Body.LinearVelocity = new Vector2(this.mf_Body.LinearVelocity.X,
                                              Math.Min(this.mf_Body.LinearVelocity.Y, this.mec_maxSpeed.Y));
}