#include<bits/stdc++.h>

#define ll long long
#define ld long double
#define pb push_back

using namespace std;

void test(){
    int l,v1,v2,t,s;
    scanf("%i %i %i %i %i",&l,&v1,&v2,&t,&s);
    int n=1;
    for(int k=0;;k++){
        if((ll)n*t>=v2-v1){
            printf("%i\n",k);
            return;
        }
        ll vvmx=l/((ll)s*(k+1));
        int ost=max(0LL,v2-vvmx-t);
        int br=ost/t;
        if(ost%t)br++;
        if(n<=br){
            printf("impossible\n");
            return;
        }
        v2=max(v1,v2-br*t);
        n=(n-br)*2;
    }
}
int main(){
    int o;
    scanf("%i",&o);
    while(o--){
        test();
    }
}