Answer:
866.32 N
Explanation:
The diagram explains better.
Taking the total moment of forces, the sum of the clockwise moment of forces about the fulcrum must be equal to the sum of the anticlockwise moment of forces about the fulcrum:
F * (1.9 - 0.65) = 170 * 9.8 * 0.65
F * 1.25 = 1082.9
F = 1082.9/1.25
F = 866.32 N
A force of 866.32 N is needed to move the rock.