Question
A bird of mass 0.8kg hovers upwards by beating the mass of effective area 0.5m^2. (i) what is its upthrust? (ii) estimate the velocity imparted to the air by beating of the wings assuming the density of air at STP to be 1.3kg/m^3.
Answers
bobpursley
upward thrust= weight of bird
massair*velocity=thrust*deltatime
massair/time *velocity=thrust
densityair*volume*velocity
densityair*area*velocity*time*veloity=thrust*time
velocity^2=thrust/(densityair*area)
massair*velocity=thrust*deltatime
massair/time *velocity=thrust
densityair*volume*velocity
densityair*area*velocity*time*veloity=thrust*time
velocity^2=thrust/(densityair*area)