To calculate how long it takes for a pulse to cover a distance of 25cm, we can use the formula:
time = distance / speed
In this case, the distance is 25cm and the speed is 0.5m/s, so we can plug in these values:
time = 25cm / (0.5m/s)
To convert cm to m we divide the distance by 100.
time = 25 / 100 m / 0.5m/s
time = 0.25s
So it takes 0.25 seconds for the pulse to cover a distance of 25cm, when the speed of the pulse is 0.5m/s.