its c!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:

Explanation:
the variations in riser height or tread depth should not be grater than
that is equal to 9.5 mm but the maximum riser height should be the
but variation in riser height should not exceed to
. The minimum riser height should be 7 inches which is equal to the 178 mm
Answer:

Explanation:
As we know that volume of cylinder is

Where v=volume , h= height or thickness and r= radius
Here,

Putting these values in the previous equation , we get

Therefore thickness is 27.5 m
Answer:
The separation between the charges was decreased by a factor of 0.2
Explanation:
The Coulomb's force between two charges is given by;

r₂ = 0.2r₁
Therefore, the separation between the charges was decreased by a factor of 0.2.