Question

please answer theese questions briefly ;

1. If a pulse is generated in slinky of length 2m and it moves 4 times in slinky within a time span of 10s and what is the speed of this pulse is ?

2.how many vibration will a turning fork of frequency 280 hertz will complete during the time sound trands forward in air by 18cm.Speed of sound in air be 336m/sec

Answer 1

1) length of slinky = 2m
time taken by wave = 10 sec.
4 times of slinky = 2*4 = 8m
speed = distance travelled by wave/time
         = 8/10
         = 0.8 m/sec.
2)  frequency = 280 sec^-1
it means it will vibrate 280 times in a second
speed of sound in air = 336m/sec.
distance travelled bu sound in air = 18cm. = 0.18m.
time taken by sound = distance/speed
                              = 0.18/336
                              = 0.00053 sec.
tuning fork take 1sec. to vibrate 280 times
so in 0.00053 second it will vibrate 0.00053*280 times = 0.15 times