Question

This lab asks you to devise two independent ways to determine the speed of a pulse on a cord. Indicate what these might be, including the quantities you will need to measure in each case [Note: You can only directly measure masses, distances, and time spans.]

Answer 1

The answer is below

Step-by-step explanation:

The first method, we find velocity of wave in a string by using the relationship

v= distance which is traveled by pulse / the duration taken for travel from one end of string to other.

v = L/T Note that V = velocity of pulse , L = length of string , T = time taken for pulse to travel length of string

Uncertainty in v = AV = V(dL/L) + (dT/T)

To decrease the uncertainty, L should be increased sufficiently large and dL should be reduced through using a measuring rod with minimal uncertainty in the measurement of L.

Similarly we should measure T with a stop clock with a low least count.

In the second method we are using

v = sqrt(TP) , where T = Tension in the string= M g , where M = mass attached to create tension in string

\rho Is the mass per unit length of string = m/ L , where m = mass of string , L = length of string

AV = 0.5 x (V)(dM/M) + (dL/L) + (dm/m)

Hence L should be maximised and least count of measuring instruments for L, m and M should be kept to minimum.