What Are the Initial Angular Velocity and Angular Acceleration of the Flywheel?

[manal950]

A flywheel makes 80 radians in 4 second and is rotating with constant angular acceleration during this time . It makes 60 radians in next 4 second with constant angular velocity .
Find initial angular velocity and the angular acceleration ?

my answer is

form this equation
Q= w0t + 1/2at^2
80 = w0(4) + 1/2(a)(4)^2 ==== 1
w = w0 + at
15 = w0 + a(4) ========= 2

so from this two equation we find a and v

 

[ehild]

Write the equation for Q after the additional 4 s time.

ehild