Alungful of air (377 cm3 ) is exhaled into a machine that measures lung capacity. if the air is exhaled from the lungs at a pressure of 1.7 atm at 41.7 ◦c but the machine is at ambient conditions of 0.958 atm and 23 ◦c, what is the volume of air measured by the machine? answer in units of cm3 .

The volume of the gas when the pressure and temperature has changed is

Explanation:

To calculate the volume when temperature and pressure has changed, we use the equation given by combined gas law.

The equation follows:

where,

are the initial pressure, volume and temperature of the gas

are the final pressure, volume and temperature of the gas

We are given:

Putting values in above equation, we get:

Hence, the volume of the gas when the pressure and temperature has changed is

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j