Question

A simple pendulum vibrates 200 times in 300 minutes what is the frequency of oscillation for the simple pendulum?

Question no. 2
Why is it easier to piece a cardboard with a sharp tip pin

Questions no. 3
An alarm bell is kept inside a vessel. A person standing close to it can distinctly hear the sound of alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person

Answer 1

NO1. Frequency=no. of vibrations completed÷time taken. Hence frequency= 200÷300 whose aproximate value is 0.7. So frequency =o.7hertz
NO2. it is easier to piece a cardboard with a sharp tin pin because when surface area decreases pressure increases & vise versa
NO3. When all air will be taken out then the sound cannot be hear as sound needs a medium to propagate