At Venus's surface, g is 8.9 N/kg. The field there pulls…
A lander settles onto an unexplored moon. Mission control wants that moon's g. The lander carries no special meter, only a known mass and a force sensor. That is enough.
You've already seen what g means: the field exerts g newtons on each kilogram. Read backward, that meaning is a measuring tool. Divide the force on a known mass by that mass, and you have g.
In g = F/m, g is the gravitational field strength in newtons per kilogram (N/kg), F is the gravitational force on the object in newtons (N), and m is the object's mass in kilograms (kg).
The Moon's field exerts 320 N on the 200 kg lander. Run the three steps you know: write down the values, select the equation, substitute.
The Moon's field exerts 320 N on a 200 kg lander. Calculate g on the Moon.
Write down the values in the question:
F = 320 N
m = 200 kg
g = ?
Write down the equation:
g = F/m
Substitute in the values:
g = 320/200
Simplify:
g = 1.6 N/kg
The answer lands in newtons per kilogram: newtons on top, kilograms underneath. That is the right unit for a field strength.
Venus's field pulls a 6.0 kg instrument with 53.4 N. Enter g in newtons per kilogram.
Europa's field pulls an 8.0 kg probe with 10.4 N. Enter g in N/kg.
The lander's twin stands on Mars, where the field exerts 740 N on the same 200 kg. Calculate g on Mars.
Write down the values in the question:
F = 740 N
m = 200 kg
g = ?
Write down the equation:
g = F/m
Substitute in the values:
g = 740/200
Simplify:
g = 3.7 N/kg
Any body in the solar system gives up its g this way: one force reading on one known mass, then one division.
Titan's field pulls a 120 kg drone with 168 N. Enter g in N/kg.
Io's field pulls a 25 kg camera sled with 45 N. Enter g in N/kg.
Pluto's field pulls a 50 kg lander leg with 31 N. Enter g in N/kg.
On the dwarf planet Ceres, the field pulls a 30 kg supply pod with 8.4 N. Enter g in N/kg.
Ganymede's field pulls a 40 kg rover with 57.2 N. Enter g in newtons per kilogram.
The same 10 kg rock is carried from the Moon to Mars. The field's pull on it is larger on Mars. Which statement is correct?
A 12 kg instrument package sits on Triton, 4.5 billion km from the Sun. Triton's field pulls the package with 9.36 N. Enter Triton's g in N/kg.