For the first third of the way, the body moved at a speed of 10 m / s

For the first third of the way, the body moved at a speed of 10 m / s, the average speed of 20 m / s to determine the speed in the second section.

Given:

The path traveled by the body is divided into two parts (1/3 and 2/3).

V1 = 10 m / s;

Vaverage = 20 m / s.

To find:

V2 -?

Decision:

So, let the path traveled by the body be S meters, then

The first part of the path (third):

S / 3 was passed at a speed of 10 m / s;

Remaining path:

2S / 3 was passed at a speed of -? m / s.

Let’s write down the ratio:

S / Vaverage = (S / 3) / 10 + (2S / 3) / V;

We get the equation:

S / 20 = S / 30 + 2S / 3V;

Let us cancel both sides of the equation by S:

2 / 3V = 1/60;

3V = 120;

V2 = 40 m / s speed on the second leg.