A light polystyrene ball is shown hanging very close to a loudspeaker. The loudspeaker gives out a sound of low frequency and the ball is seen to vibrate.

a. Explain how the sound from the loudspeaker causes the ball to move as described.

b. Explain what will happen to the motion of the cone of the loudspeaker when:

i. The sound is made louder

ii. The pitch of the sound is increased.

c. Calculate the frequency of a sound which has a wavelength of 0.5 m and travels at a speed of 340 m/s in air. Write down the formula that you use and show your working.