The boy throws pebbles into the well and calculates the distance to the water in the well according to the formula

The boy throws pebbles into the well and calculates the distance to the water in the well according to the formula s = 5t ^ 2 where s is the distance in meters, t is the fall time in seconds. After the rain the water level rose. Find how many meters the water level in the well has risen if to rainfall time was 0.6 s and after rain the measured time changed by 0.2 s.

Let’s calculate S0 – the distance from water to rain:

S0 = 5 * 0.6 ^ 2 = 5 * 0.35 = 1.8m.

Let’s find the time after the rain:

0.6 – 0.2 = 0.4s.

Then S1 – the distance after the rain will be equal to:

S1 = 5 * 0.4 ^ 2 = 5 * 0.16 = 0.8m.

The difference in water levels will be:

1.8 – 0.8 = 1 m.

Answer: 1 m.