Question

Air flows steadily through an engine at a constant temperature of 400k. Find the work per kilogram if the exit pressure is one-third the inlet pressure and the inlet pressure is 207 KPa. Assume that the kinetic energy and potential energy variation is negligible.

Answer 1

Velocity of the ball at maximum height is zero, v=0

$v ^2 −u ^2 =2aH$

$0−(49) ^2 =2×(−9.8)×H$

H=122.5 m   

v=u+at

0=49−9.8t

t=5s

Total time taken by ball to return to the surface, T=2t=10 s