How much work is done when you push a 50kg refridgerator across the room for 3 meters?
None, if you ignore friction. Work requires a force, gravity is upwards. In reality, work is done in pushing horizontally, but that is due to friction, not mentioned here.
I had another problem similar to this one. It was: How much work is done to lift 3 boxes onto a 2 meter high shelf and each box has a mass of 12kg. I got 706.32 as my answer..are those 2 problems at all alike?
No. The second problem is lifting, working against gravity. You did it correctly (3*12*9.8*2) which is your answer in Joules.
The problem moving across the room involves no change in height, thus, no work (Unless you consider friction).
Thanks! You've been so helpful!