# The skier left the mountain 40m long in 10s, after which he drove horizontally to a stop of 20m, considering the two equal.

**The skier left the mountain 40m long in 10s, after which he drove horizontally to a stop of 20m, considering the two equal. Find the speed of the skier at the end of the mountain and the average speed along the way.**

Given:

v0 = 0,

s1 = 40m,

t1 = 10s,

s2 = 20m,

v2 = 0;

Find: v1 -? Vav -?

With uniform motion, the distance traveled can be found from the equation:

s1 = (v0 + v1) * t1 / 2 = v1 * t / 2;

Here v0 and v1 are the body velocities at the beginning of the section and at the end;

From here we find:

v1 = 2 * s1 / t1 = 8m / s;

We can write a similar equation for the second section of the path to find the time spent on it:

s2 = (v1 + v2) * t2 / 2 = v1 * t2 / 2;

t2 = 2 * s2 / v1 = 5s;

Average speed is determined by the ratio of the total distance traveled to the time spent:

Vav = s / t,

where

s = s1 + s2 = 40m + 20m = 60m;

t = t1 + t2 = 10s + 5s = 15s;

Vav = 60m / 15s = 4m / s.