Question

a light pointer fixed to one prong of a tunning fork touches a vertical smoked plate.the fork is set into vibration and the plate is allowed to fall freely eight complete waves are counted when the plate falls through 10centimetre. the frequency of the tunning fork

Answer 1

given:
number of oscillations =8
distance d=10 cm =0.1m
gravity g=9.8

to find :
ferquency (F) of fork.

solution:
initially we need to find time elapsed when plate fell

d=1/2 g t^2 => t^2=2d/g

so t=√(2d/g)
t=√(2*0.1/9.8) =√0.02
t=0.15 s

Answer 2

S=10cm, 0.1m

No of oscillation =8

Time =√2h/g

t = √2*0.1/10

t = √0.02 =0.141

Frequency = no of oscillation/time period

= 8/0.141 = ~56 hz