Answer:
1350 m/s
Explanation:
Speed of bullet
Distance traveled by the bullet = 450 m
Distance traveled by sound = 450 m
Using S= V × t
==> t= S/V
So, time for bullet t1=450/vb
time for sound t2=450/vs
Because it takes 1/2 sec from firing to hearing of sound by the shooter
==> t1+t2= 1/2 sec
==> 450/vb+450/vs=0.5sec ---- (1)
Now a person at distance 'x' each from gun and target takes 3 sec to hear sound from firing to hitting the target.
Fire sound duration
Distance =x m
Speed of sound = V
time =T1
==> T1 = x/vs
Bullet hitting + target sound duration
During this duration bullet travels a distance of 450 m and sound of hitting travels a distance 'x'
time taken by sound = 450/vb
time taken by sound to travel distance 'x'= x/vs
so let T2= 450/vb + x/vs
But all this happens in 3 sec i-e T = 3 sec
and because firing occurs before hitting the target so he hears strike sound in time T = T2-T1= 450/vb + x/vs -x/vs
But T= 3sec
==> 3= 450/vb
==> vb= 1350 m/s
From eq 1 and 2
again using same relation as above, i-e within 3 seconds he watches bullet traveling a distance of 450 m and hearing sound
