Moments and Force: Calculating Distance and Mass of a Caravan

[radaway]

Homework Statement

see the image of the caravan .if it is attached to a car, the caravan according to the safety regulations should exert a force of 690 N (6,9x 100 N) exerting downward on the car's tow hitch.
Before the person fastens the caravan, he checks the magnitude of the force by holding the caravan in equilibrium with a spring balance. the spring balance shows a force of 690 N. See image. also see the pivot point S and the center of gravity Z of the caravan The the caravan is drawn to scale.

a What is the distance from the pivot point S of the two forces acting on the caravan.

b Determine from the figure, the mass of the empty caravan.

Homework Equations

http://s6.postimg.org/tn1450ych/image.png[/B]

The Attempt at a Solution

n.a[/B]

 

[gneill]

Hi radaway. You need to make an attempt at solution before help can be offered. And you haven't supplied any relevant equations (Your image is should be part of the problem statement). What physics principles are involved?