We r made of atom so v can’t touch anything hehe I just joking
Answer:
the charge per unit area on the plastic sheet is - 3.23 x 10⁻⁷ C/m²
Explanation:
given information:
styrofoam mass, m = 16 g = 0.016 kg
net charge, q = - 8.6 μC
to calculate the charge per unit area on the plastic sheet, we can use the following equation:

where
the force between the electric field
m = mass
g = gravitational force

where
q = charge
E = electric field
and
E = σ/2ε₀
where
ε₀ = permitivity
thus

mg = qσ/2ε₀
σ = (2mg ε₀)/q
= 2 (0.016) (9.8) (8.85 x 10⁻¹²)/( - 8.6 x 10⁻⁶)
= - 3.23 x 10⁻⁷ C/m²
Here we deal with a lever law. It states that product of force and distance from a fixed point on a lever is equal on both sides.
F₁*d₁ = F₂*d₂
By analysing this formula we can see that applying small force on a great length equals great force on a small length.
To remove nail we need to apply certain force. If we use F₁ for this required force we can see that on other side we need to apply certain force. If we have greater arm length we need smaller force. In a crowbar arm length along which we apply force is greater than length of our arm. This leads to a conclusion that we need smaller force when using crowbar. Depending on the length of a nail it is possible that we need to apply force that is greater than force required to remove nail.