Answer:
the resistance of the second wire is 1 ohm.
Explanation:
Given;
cross sectional area of the first wire, A₁ = 5.00 x 10⁶ m²
resistance of the first wire, R₁ = 1.75 ohms
cross sectional area of the second wire, A₂ = 8.75 x 10⁶ m²
resistance of the second wire, R₂ = ?
The resistance of a wire is given as;
R ∝ 
Since the length of the two wires is constant
R₁A₁ = R₂A₂

Therefore, the resistance of the second wire is 1 ohm.
Answer:
part (a) 
Part (b) 
Explanation:
Given,
- Mass of the larger disk =

- Mass of the smaller disk =

- Radius of the larger disk =

- Radius of the smaller disk =

- Mass of the block = M = 1.60 kg
Both the disks are welded together, therefore total moment of inertia of the both disks are the summation of the individual moment of inertia of the disks.

part (a)
Given that a block of mass m which is hanging with the smaller disk,
Let 'T' be 'a' be the tension in the string and acceleration of the block.
From the free body diagram of the smaller block,

From the pulley,

From the equation (1) and (2),

part (b)
Above expression for the acceleration of the block is only depended on the radius of the pulley.
Radius of the larger pulley = 
Let
be the acceleration of the block while connecting to the larger pulley.