966 B | 966 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
# sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
n, M = input().split()
n = int(n)
M = float(M)
l = [mfi() for _ in range(n)]
g = 9.81
current_m = M
ans = 0
for m, t, F in l:
current_m += m
v = 0
for m, t, F in l:
a = F / current_m - g
ans += v * t + 1 / 2 * a * t * t
v += a * t
current_m -= m
p(f"{ans:.2f}")
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
p(f"Data Set {t}:")
ret = solve()