Answer:
132.22 N
Step-by-step explanation:
Weight at the surface of a planet is:
W = GMm / r²
where G is the gravitational constant,
M is the mass of the planet,
m is the mass of the object,
and r is the radius of the planet.
On Earth:
680 N = GMm / r²
If Earth's mass and radius were changed:
W = G (7M) m / (6r)²
W = 7/36 GMm / r²
W = 7/36 (680 N)
W = 132.22 N