The answer is 4.0 kg since the flywheel comes to rest the
kinetic energy of the wheel in motion is spent doing the work. Using the
formula KE = (1/2) I w².
Given the following:
I = the moment of inertia about the
axis passing through the center of the wheel; w = angular velocity ; for the
solid disk as I = mr² / 2 so KE = (1/4) mr²w². Now initially, the wheel is spinning
at 500 rpm so w = 500 * (2*pi / 60) rad / sec = 52.36 rad / sec.
The radius = 1.2 m and KE = 3900 J
3900 J = (1/4) m (1.2)² (52.36)²
m = 3900 J / (0.25) (1.2)² (52.36)²
m = 3.95151 ≈ 4.00 kg
Its A The paper clip is repelled away from the nail because an electromagnetic field magnetized to the nail
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