Air enters a 28-cm diameter pipe steadily at 200 kPa and 20°C with a velocity of 5 m/s. Air is heated as it flows and leaves the pipe at 180 kPa and 40 °C. Determine the mass flow rate of air and the velocity at the exit.

The mass flow rate of air is 0.732 kg/s.

The velocity at the exit is 5.927 m/s.

Explanation:

Given that,

Diameter = 28 cm

Enter pressure= 200 kPa

Enter temperature = 20°C

Velocity = 5 m/s

Exit pressure = 180 kPa

Exit temperature = 40°C

We need to calculate the mass flow rate of air

Using formula of mass flow rate

Put the value into the formula

We need to calculate the volume flow rate

Using formula of volume flow rate

We need to calculate the velocity at the exit

Using formula of velocity

Put the value into the formula

Hence, The mass flow rate of air is 0.732 kg/s.

The velocity at the exit is 5.927 m/s.

the answer is b

explanation:

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min