#include <bits/stdc++.h>
using namespace std;
long long rdtsc() {
  long long tmp;
  asm("rdtsc" : "=A"(tmp));
  return tmp;
}
inline int myrand() { return abs((rand() << 15) ^ rand()); }
inline int rnd(int x) { return myrand() % x; }
const int INF = (int)1.01e9;
const long double EPS = 1e-9;
void precalc() {}
int mx1, my1, x2, y2;
int vs[2][2];
int vmax, tch;
bool read() {
  if (scanf("%d%d%d%d%d%d", &mx1, &my1, &x2, &y2, &vmax, &tch) < 6) {
    return 0;
  }
  for (int i = 0; i < 2; ++i) {
    scanf("%d%d", vs[i], vs[i] + 1);
  }
  return 1;
}
void solve() {
  long double left = 0, right = 1e18;
  for (int iter = 0; iter < 120; ++iter) {
    long double mid = (left + right) / 2;
    long double x = mx1, y = my1;
    if (mid <= tch) {
      x += mid * vs[0][0], y += mid * vs[0][1];
    } else {
      x += tch * vs[0][0], y += tch * vs[0][1];
      x += (mid - tch) * vs[1][0], y += (mid - tch) * vs[1][1];
    }
    x -= x2, y -= y2;
    long double tme = sqrt(x * x + y * y) / vmax;
    if (tme <= mid) {
      right = mid;
    } else {
      left = mid;
    }
  }
  printf("%.18f\n", (double)right);
}
int main() {
  srand(rdtsc());
  precalc();
  while (1) {
    if (!read()) {
      break;
    }
    solve();
  }
  return 0;
}
