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

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia