Login

A construction worker's helmet slips and falls when he is 78.4m above the ground, he hears the sound of the helmet hitting the ground 4.23s after it slipped.Find the speed of the speed of sound in air.

Case I: Time taken by helmet to reach groundt1=2hg =2×78.49.8  =4 sCase II: Time taken by sound to reach the wroker from the groundt2=hv   =78.4vTotal time taken, t =4.23 sHence, t2=t-t1                =4.23 - 4                 =0.23 sVelocity of sound:v=78.4t2  =78.40.23  =340.9 m/s

  • 4
View Full Answer
is answer 340.86 m/s if yes i will eplain it reply
  • 2
 here , height=78.4m
he hears sound after 4.23 seconds which includes time taken by the helmet to go down to the ground &the time taken by the sound of striking back to the worker
initial velocity(u)= 0
acceleration due to gravity=    -9.8
using second equation of motion
                                             s  = u  * t +a *( t)2 
78.4=0 * t +1/2 
 
  • 1
What are you looking for?