A solid disk, spinning counter-clockwise, has a mass of #5 kg# and a radius of #8 m#. If a point on the edge of the disk is moving at #6 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer

Answer:

#120\ \text{kgm}^2\text{/s}# & #0.75\ \text{rad /s}#

Explanation:

Mas of solid disk #m=5\ kg#

Radius of solid disk #r=8\ m#

Peripheral speed of disk #v=r\omega=6\ m/s#

The angular velocity #\omega# of the disk

#\omega=v/r=6/8=0.75\ \text{rad/s}#

Mass moment of inertia (#I#) of solid disk

#I=1/2mr^2=1/2(5)(8)^2=160\ kgm^2#

Now, the angular momentum #J# of the solid disk is given as

#J=I\omega#

#=160\cdot 0.75#

#=120\ \text{kgm}^2\text{/s}#