C..............................
A natural frequency of vibrations determined by the physical parameters of the vibrating object.
Answer:
I = 2 kgm^2
Explanation:
In order to calculate the moment of inertia of the door, about the hinges, you use the following formula:
(1)
I: moment of inertia of the door
α: angular acceleration of the door = 2.00 rad/s^2
τ: torque exerted on the door
You can calculate the torque by using the information about the Force exerted on the door, and the distance to the hinges. You use the following formula:
(2)
F: force = 5.00 N
d: distance to the hinges = 0.800 m
You replace the equation (2) into the equation (1), and you solve for α:

Finally, you replace the values of all parameters in the previous equation for I:

The moment of inertia of the door around the hinges is 2 kgm^2
Answer: 
Explanation:
The de Broglie wavelength
is given by the following formula:
(1)
Where:
is the Planck constant
is the momentum of the atom, which is given by:
(2)
Where:
is the mass of the electron
is the velocity of the electron
This means equation (2) can be written as:
(3)
Substituting (3) in (1):
(4)
Now, we only have to find
:
>>> This is the de Broglie wavelength of the electron
Answer:
F-F(gr) = ma
a= {F-F(gr)}/m =
=(15-10)/15=0.33 m/s² (upward)