Answer:
1/2mv² = ke²
Explanation:
Let's suppose the material in question is a spring with spring constant k, mass m and position k, the kinetic energy possessed by the string will be;
K.E = 1/2mass×velocity² i.e 1/2mv²
Its elastic potential energy will be the work done on the spring when stretched which is equal to 1/2kx²
E.P = 1/2kx²
The equation describing the case where the kinetic energy is twice the elastic potential energy will be;
K.E = 2EP... 1)
Substituting the KE and EP formula into (1), we have;
1/2mv² = 2(1/2ke²)
1/2mv² = ke² which gives the required equation
Answer:
The rate at which the container is losing water is 0.0006418 g/s.
Explanation:
- Under the assumption that the can is a closed system, the conservation law applied to the system would be:
, where
is all energy entering the system,
is the total energy leaving the system and,
is the change of energy of the system. - As the purpose is to kept the beverage can at constant temperature, the change of energy (
) would be 0. - The energy that goes into the system, is the heat transfer by radiation from the environment to the top and side surfaces of the can. This kind of transfer is described by:
where
is the emissivity of the surface,
known as the Stefan–Boltzmann constant,
is the total area of the exposed surface,
is the temperature of the surface in Kelvin,
is the environment temperature in Kelvin. - For the can the surface area would be ta sum of the top and the sides. The area of the top would be
, the area of the sides would be
. Then the total area would be 
- Then the radiation heat transferred to the can would be
. - The can would lost heat evaporating water, in this case would be
, where
is the rate of mass of water evaporated and,
is the heat of vaporization of the water (
). - Then in the conservation balance:
, it would be
. - Recall that
, then solving for
:
25 x 10^-5
= 0.00025
25 cm
= 0.00025 km
The Bohr's proposal for the angular momentum of an electron in Bohr's model of the hydrogen atom is:
L=(n*h)/(2π), where n is the number of the energy level and h is the Planck's constant. This equation shows us the quantization of angular momentum of the electron. So the correct answer is the second one: Planck's constant.
Force-a push or pull exerted on an object.