Answer:
31.2 m/s
Explanation:
= Frequency of approach = 480 Hz
= Frequency of going away = 400 Hz
= Speed of sound in air = 343 m/s
= Speed of truck
Frequency of approach is given as
eq-1
Frequency of moving awayy is given as
eq-2
Dividing eq-1 by eq-2
= 31.2 m/s
The correct answer is:
Work is negative, the environment did work on the object, and the energy of the system decreases.
In fact, the work-energy theorem states that the work done by the system is equal to its variation of kinetic energy:
In this problem, the variation of kinetic energy is negative (because the final velocity is less than the initial velocity), so the work is negative, and this means that the environment did work on the object, and its energy decreased.
Answer:
The final pressure of the gas is 9.94 atm.
Explanation:
Given that,
Weight of argon = 0.16 mol
Initial volume = 70 cm³
Angle = 30°C
Final volume = 400 cm³
We need to calculate the initial pressure of gas
Using equation of ideal gas
Where, P = pressure
R = gas constant
T = temperature
Put the value in the equation
We need to calculate the final temperature
Using relation pressure and volume
Hence, The final pressure of the gas is 9.94 atm.
