During the launch from a board, a diver's angular speed about her center of mass changes from zero to 6.90 rad/s in 250 ms. her rotational inertia about her center of mass is 12.0 kg·m2.
a. during the launch, what was the magnitude of her average angular acceleration?
b. during the launch, what was the magnitude of the average external torque on her from the board?

a) α = 27.6 rad/s²

b) τ = 331.2 N*m

Explanation:

Given:

ωinitial = 0 rad/s

ωfinal = 6.90 rad/s

Δt = 250 ms = 0.25 s

I = 12.0 Kg*m²

a) We can use the equation

α = Δω / Δt

α = (ωfinal - ωinitial) / Δt

⇒  α = (6.90 rad/s - 0 rad/s) / 0.25 s

⇒  α = 27.6 rad/s²

b) we apply the formula

τ = I*α  ⇒  τ = (12.0 Kg*m²)*(27.6 rad/s²)

⇒  τ = 331.2 N*m

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)