In: Physics
QUESTION 1
A disk (radius 13.5 cm] rotates about a fixed axis through its center of mass and perpendicular to the disk. At t = 0 the disk is rotating at frequency 6.64 Hz, and it accelerates uniformly to frequency 27.6 Hz after spinning through 60.4 revolutions. Find the angular acceleration of the disk, in rad/s2.
QUESTION 2
The wheel of a cart has radius 64.6 cm. How many revolutions will it make if the cart goes 6.45 km?
Multiple questions posted, so answeing only the first question:
1. angular velocity is given by:=2
f,
where
is angular velocity, f is frequency.
Initial frequency=6.64 Hz
So,initial angular velocity
i= 2
*6.64=41.72
rad/s.
Final frequency=27.6 Hz
So,final angular velocity
f= 2
*27.6=173.42
rad/s.
Angular displacement
=60.4 revolutions=60.4*2
=379.5
radians.
Now,in uniform acceleration,
f2=
i2+2
,
where
f is final angular velocity,
i
is initial angular velocity,
is angular acceleration,
is angular displacement.
So,173.422=41.722+2*379.5
=>2*379.5=173.422-41.722=28333.938
=>=28333.938/(2*379.5)=37.33
rad/s2