Answer:
I = 0.4 kg m²
Explanation:
Let's solve this exercise in part, let's first work with the cube.
W -T = m a
T = W - m a
T = m (g-a)
T = 10.0 (9.8 - 4.9)
T = 49 N
Now let's work on the pinwheel, we write Newton's rotational law
τ = I α
T r = I α
Linear and angular variables are related.
a = α r
α = a / r
We replace
T r = I a / r
I = T r² / a
we calculate
I = 49 0.20² / 4.9
I = 0.4 kg m²