A person standing at a distance x in front of a cliff fires a gun. Another person B standing behind the person A at a distance y from the cliff hears two sounds of the fired shot after 2 s and 3 s respectively. Calculate x and y (take speed of sound 320 ms^-1)

On sending an ultrasonic wave from a ship towards the bottom of a sea, the time interval between sending the wave and receiving it back is found to be 1.5 s. If the velocity of the wave in sea water is 1400 ms^-1, find the depth of sea.

The period (or frequency) of natural vibrations depends on :

1. shape
2. size
3. external force
4. both (1) and (2)

The natural frequency of a simple pendulum of length 1.0 m on earth's surface is :

[Take g = 9.8 m/s²]

1. 0.5 Hz
2. 100 Hz
3. 50 Hz
4. 5 Hz