#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;



void solve()
{
	int l, v1, v2, t, s;
	cin >> l >> v1 >> v2 >> t >> s;
	
	int k = 0;
	while((1LL << k) * t < v2 - v1)
		k++;
	if(k <= (l / (v2 * (LL)s)))
	{
		cout << k << "\n";
		return;
	}
	int ans = 0;	
	
	int cnt = 0;
	while(v2 - v1 > t)
	{
		auto check = [&](int num)
		{
			if(num > 30 || v2 <= t * (1LL << num))
				return false;
			
			FOR(i, 0, num)
			{
				int v = v2 - t * (1 << (num - 1 - i));
				if(cnt + i + 1 > l / (v * s))
					return false;
			}
			return true;
		};
		if(!check(1))
		{
			cout << "impossible\n";
			return;
		}
		
		int mx = 1;
		while(check(mx)) mx++;
		mx--;
		
		k = mx;
		
		v2 = v2 - t * (1 << (k - 1));
		//cerr << cnt << " " << mx << " " << v2 << "\n";
		
		ans = max(ans, cnt + mx);
		cnt++;
	}
	cout << ans << "\n";
}


int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	
	int t;
	cin >> t;
	while(t--)
		solve();
	
	return 0;
}