39b. Anthony sends a series of pulses of amplitude 24 cm down a string that is attached to a post at one end Assuming the pulses are reflected with no loss of amplitude, what is the amplitude at a point on the string where two pulses are crossing if the end at which reflection occurs is free to slide up and down? ). 0 cm 12.cm 24 cm .48 cm

## Step 1<br />This problem involves the concept of wave interference, which is a phenomenon that occurs when two or more waves of the same type meet and combine to form a new wave. In this case, the waves are pulses of amplitude 24 cm sent down a string.<br /><br />## Step 2<br />The problem states that the pulses are reflected with no loss of amplitude. This means that the amplitude of the reflected pulse is the same as the amplitude of the incident pulse, which is 24 cm.<br /><br />## Step 3<br />The problem also states that the end at which reflection occurs is free to slide up and down. This means that the amplitude of the reflected pulse is not reduced by any friction or other forces.<br /><br />## Step 4<br />When two pulses of the same amplitude and frequency meet, they interfere constructively. This means that the amplitudes of the two pulses add together to give the amplitude of the resulting wave.<br /><br />## Step 5<br />Since the amplitude of each pulse is 24 cm, the amplitude of the resulting wave when the two pulses meet is \(2 \times 24\) cm = 48 cm.