Answer:

Explanation:
The equivalent of Newton's second law for rotational motions is:

where
is the net torque applied to the object
I is the moment of inertia
is the angular acceleration
In this problem we have:
(net torque, with a negative sign since it is a friction torque, so it acts in the opposite direction as the motion)
is the moment of inertia
Solving for
, we find the angular acceleration:

Answer:
VR=2
Explanation:
driven=60
driving=30
but VR=driven/driving
VR=60/30
VR=2
hence the velocity ratio VR is 2
#1).
transfers energy ... both kinds of waves do that
travels in a vacuum ... mechanical waves can't do that
has frequency ... both kinds of waves have
requires a medium ... electromagnetic waves don't need it
2).
infrared, visible, ultraviolet
listed from longest to shortest wavelength
Efficiency or
is calculated by formula:
where
also efficiency has no unit.
Now put in the data and calculate the efficiency.

The efficiency of the machine is 0.8
If you want to get percentage just multiply by 100 and you get 80%
Hope this helps.
r3t40
Answer:
19,551 J!
Explanation:
The formula is PE = ham (h=height, a= acceleration or 9.8, m= mass)
PE = (95)(9.8)(21)
PE = 19,551 Joules