Answer: 166.67km/hr
Explanation:
Given the following :
Distance traveled = 250km
Time taken = 1.5 hours
Recall :
Speed = Distance traveled / time taken
Speed = 250 km / 1.5 hours
Speed = 166. 67 km/hr
Speed in m/s:
166.67km/hr = (166.67 × 1000)m / 3600 s
= 166670m / 3600s
= 46.3m/s
Answer:
B. d(low)=4d(high)
Explanation:
Frequency of a string can be written as;
f = v/2L
Where;
v = sound velocity
L = string length
Frequency can be further expanded to;
f = v/2L = (1/2L)√(T/u) ......1
Where;
m= mass,
u = linear density of string,
T = tension
p = density of string material
A = cross sectional area of string
d = string diameter
u = m/L .......2
m = pAL = p(πd^2)L/4 (since Area = (πd^2)/4)
f = (1/2L)√(T/u) = (1/2L)√(T/(m/L))
f = (1/2L)√(T/((p(πd^2)L/4)/L))
f = (1/2L)√(4T/pπd^2)
f = (1/L)(1/d)√(4T/pπ)
Since the length of the strings are the same, the frequency is inversely proportional to the string diameter.
f ~ 1/d
So, if
4f(low) = f(high)
Then,
d(low) = 4d(high)
To solve this problem it is necessary to apply an energy balance equation in each of the states to assess what their respective relationship is.
By definition the energy balance is simply given by the change between the two states:

Our states are given by



In this way the energy balance for the states would be given by,



Therefore the states of energy would be
Lowest : 0.9eV
Middle :7.5eV
Highest: 8.4eV
The equation of state for an ideal gas is

where p is the gas pressure, V the volume, n the number of moles, R the gas constant and T the temperature.
The equation of state for the initial condition of the gas is

(1)
While the same equation for the final condition is

(2)
We know that in the final condition, half of the mass of the gas is escaped. This means that the final volume of the gas is half of the initial volume, and also that the final number of moles is half the initial number of moles, so we can write:


If we substitute these relationship inside (1), and we divide (1) by (2), we get

And since the initial temperature of the gas is

, we can find the final temperature of the gas: