Adrum rotates around its central axis at an angular
velocityof 12.60rad/s. if the drum then slows at a constant rate
of4.20rad/s2, a) how much time does it take and b)
throughwhat angle does it rotate in coming to rest?

a)t= 3 s

b)θ = 18.9 rad

Explanation:

Given that

Initial angular velocity ,ωi = 12.6 rad/s

Acceleration ,α = - 4.2 rad/s²

Final angular speed ,ωf = 0 rad/s

We know that

ωf =ωi + α t

t=Time

Now by putting the values

0 = 12.6 - 4.2 x t

t= 3 s

We also know that

ωf² =ωi² + 2 α θ

θ=Angle

Now by putting the values

0² =12.6² -  2 x 4.2 x θ

θ = 18.9 rad

a)t= 3 s

b)θ = 18.9 rad

d. air pressure decreases as altitude increases.

the area between the graph and the t axis