6. Four people are trying to help push and lift a refrigerator up a series of stairs. Jim pushes
with a force of 60 N. Aaron lifts with a force of 200 N. Reginald pushes with a force of 210 N,
and Archer lifts with a force of 95 N.

Net force due to all on the refrigerator is 400 N

Explanation:

As we know that two people are pushing the refrigerator while other two people are lifting the refrigerator

So net push force on the refrigerator is given as

Similarly net lift force on the refrigerator is given as

Now net force on the refrigerator is given as