Answer:
The minimum angular speed 57.0 rad/s
Explanation:
In this exercise we must use the relationships between the angular and linear magnitudes, for the speeds we have
v = w r
As they give us that linear velocity is constant, we will calculate the angular velocity for the two radii, external and internal
r1 = 11.75 cm (1 m / 100cm) = 0.1175 m
w1 = v / r1
w1 = 6.70 / 0.1175
w1 = 57.0 rd / s
R2 = 4.50 cm = 0.0450 m
w2 = 6.70 / 0.0450
w2 = 148 rad / s
The minimum angular speed 57.0 rad / s
Answer:

Explanation:
According to the given reaction,
heat released by thecombustion of 2 molecules of Methanol, 
we know that molecular mass of Methanol, 
∴12 gram of methanol = 
we know 1 mole = 
so,

Heat from the combustion of
:


<u>Now the mass of water that can be heated from 23.5°C to 88.2°C :</u>



Answer:
if the intensity of photons is constant then number of ejected electrons will remain same
Explanation:
As per photoelectric effect we know that when light of sufficient frequency fall on the surface of metal then electrons get ejected out of the surface with certain kinetic energy
Here the energy of photons is used to eject out the electrons from metal surface and to give the kinetic energy to the ejected electrons
so we have

here W = work function of metal which shows the energy required to eject out electrons from metal surface
KE = kinetic energy of ejected electrons
now if we increase the frequency of the photons that incident on the metal surface then in that case the incident energy will increase
So the electrons will eject out with more kinetic energy while if the number of photon is constant or the intensity of photons is constant then number of ejected electrons will remain same