Find the net gravitational force?

[wasi90lk]

Homework Statement

three planets, X,Y and Z, are situated in 3 different places.

distance between X and Y = 60 x 10⁶ km

distance between Y and Z = 50 x 10⁶ km

mass of X = 3.0 x 10²⁴ kg

mass of Y = 4.0 x 10²⁴ kg

mass of Z = 5.0 x 10²⁴ kg

find the net gravitational force on planet Z.

Homework Equations

F = Gm₁m₂/r²

The Attempt at a Solution

i am not sure where to start.

 

[LowlyPion]

Homework Statement

three planets, X,Y and Z, are situated in 3 different places.

distance between X and Y = 60 x 10⁶ km
distance between Y and Z = 50 x 10⁶ km

mass of X = 3.0 x 10²⁴ kg
mass of Y = 4.0 x 10²⁴ kg
mass of Z = 5.0 x 10²⁴ kg

find the net gravitational force on planet Z.

Homework Equations

F = Gm₁m₂/r²

The Attempt at a Solution

i am not sure where to start.

You would expect to solve by superposition, in adding the force of XZ and YZ. But what is the distance from X to Z? Is there a diagram? Is there a typo? Are they all 3 in a row?

 

[wasi90lk]

they are all in a row. distance between X and Z isn't given, but we can get that by adding distance of X+Y and distance of Y+Z.

 

[LowlyPion]

they are all in a row. distance between X and Z isn't given, but we can get that by adding distance of X+Y and distance of Y+Z.

OK. So solve it then. You have the right formula.