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A uniform-density disk of mass 13 kg, thickness 0.5 m. and radius 0.2 m make one complete rotation every 0.6 s. What is the rotational kinetic energy of the disk?

Short Answer

Expert verified

The rotational kinetic energy is,14.26 J .

Step by step solution

01

Identification of the given data

The given data can be listed below as,

  • The mass of disk is, m=13 kg.
  • The thickness of disk is, t=0.5 m .
  • The radius of disk is,r=0.2 m .
  • The rotation period is, T=0.6 s.
02

Significance of rotational kinetic energy

The rotational kinetic energy is the rotational kinetic energy of a rotating rigid body or particle system.

03

Determination of the rotational kinetic energy

The relation of rotational kinetic energy is expressed as,

Krot=12I2 ...(i)

Here Krotis the rotational kinetic energy, is the angular speed and Iis the moment of inertia.

The value of the moment of inertia and angular velocity for the disk is expressed as,

I=12mr2

And

=2T

Here m is the mass of disk, r is the radius of disk and T is the rotation period.

Substitute the value of Tand in the equation (i).

Krot=1212mr22T2Krot=14mr22T2

Substitute 13kgform,0.2mforr,and0.6sforTin the above equation.

Krot=1413kg0.2m22T2=14.26J

Hence the rotational kinetic energy is,14.26J.

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