Answer:
<em>His angular velocity will increase.</em>
Explanation:
According to the conservation of rotational momentum, the initial angular momentum of a system must be equal to the final angular momentum of the system.
The angular momentum of a system = 
'ω'
where
' is the initial rotational inertia
ω' is the initial angular velocity
the rotational inertia = 
where m is the mass of the system
and r' is the initial radius of rotation
Note that the professor does not change his position about the axis of rotation, so we are working relative to the dumbbells.
we can see that with the mass of the dumbbells remaining constant, if we reduce the radius of rotation of the dumbbells to r, the rotational inertia will reduce to .
From
'ω' = ω
since is now reduced, ω will be greater than ω'
therefore, the angular velocity increases.
Answer:
I = 8.75 kg m
Explanation:
This is a rotational movement exercise, let's start with kinetic energy
K = ½ I w²
They tell us that K = 330 J, let's find the angular velocity with kinematics
w² = w₀² + 2 α θ
as part of rest w₀ = 0
w = √ 2α θ
let's reduce the revolutions to the SI system
θ = 30.0 rev (2π rad / 1 rev) = 60π rad
let's calculate the angular velocity
w = √(2 0.200 60π)
w = 8.683 rad / s
we clear from the first equation
I = 2K / w²
let's calculate
I = 2 330 / 8,683²
I = 8.75 kg m
Answer:
Explanation:
velocity of light in a medium of refractive index V = V₀ / μ
V₀ is velocity of light in air and μ is refractive index of light.
time to travel in tube with air = length of tube / velocity of light
8.72 ns = L / V₀ L is length of tube .
time to travel in tube with jelly = length of tube / velocity of light
8.72+ 1.82 = L / V L is length of tube .
10.54 ns = L / V
dividing the equations
10.54 / 8.72 = V₀ / V
10.54 / 8.72 = μ
1.21 = μ
refractive index of jelly = 1.21 .
Missing information
Consider a superconducting MRI magnet for which the magnet field decreases from 8.0 T to nearly 0 in 20 s
Answer:
0.152 mV
Explanation:
Change in magnetic field, dB=8-0=8 T
Time interval, dt=20 s
Diameter of ring= 2.2cm hence radius is 1.1 cm equivalent to 0.011
where n is the number of terms and for this question n=1 and A is area which is given by 
hence
and substituting the values
Therefore, induced emf is 0.152 mV
F=mass x acceleration = ma= 0.8*20 = 16N
