Ahydraulic device is used to lift a block of 15 kg mass by 5 cm. (a) if the ratio of areas is a/a = 10, what force is required to do the lifting assuming the weight of the fluid is neglected?

To solve this problem it is necessary to use the concepts related to pressure. The pressure can be defined as

Due to the continuity and pressure conservation relationship, the pressure must be preserved to support the weight (gravity) and to lift it (lift)

In this way,

That is equal to

We have a ratio of A/a = 10, then

Therefore the force required to do the lifting is 147.15N

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.