Answer:
The work done by gravity moving the box up is -514.5 Joules.
Explanation:
The gravity acts in the direction of the displacement, which in this case is negative (ground - top shelf), and so the resulting work is negative. The work is calculated as:

The work done by gravity moving the box up is -514.5 Joules.
They carry opposite charge ( one has negative charge and one has positive charge)
Answer:
840 cm
Explanation:
Note: A hydraulic press operate based on pascal's principle.
From pascal's principle
W₁/d₁ = W₂/d₂...................... Equation 1
Where W₁ and W₂ are the first and second weight, and d₁ and d₂ are the first and second diameter of the piston.
make d₁ the subject of the equation
d₁ = W₁×d₂/W₂................ Equation 2
Given: W₁ = 2100 kg, W₂ = 25 kg, d₂ = 10 cm = 0.1 m.
Substitute these values into equation 2
d₁ = 2100(0.1)/25
d₁ = 8.4 m
d₁ = 840 cm
Jupiter that is the answer
good luck