A skier descending from a mountain goes 50 meters in 5 seconds, after descending from a mountain

A skier descending from a mountain goes 50 meters in 5 seconds, after descending from a mountain and continuing to move until a complete stop, he goes another three meters in 15 seconds. Find the average speed of the skier for the entire time of movement.

t1 = 5 s.

S2 = 3 m.

t2 = 15 s.

Vav -?

To find the average speed Vav of a skier, it is necessary to divide the entire path S he has traveled by the time t of its passage: Vav = S / t.

The path S traversed by the skier will be the sum: S = S1 + S2, where S1 is the skier’s path from the mountain, S2 is the horizontal path of the skier.

S = 50 m + 3 m = 53 m.

The travel time of the entire path t will also be the sum: t = t1 + t2, where t1 is the time of descent from the mountain, t2 is the time of horizontal movement.

t = 5 s + 15 s = 20 s.

Vav = 53 m / 20 s = 2.65 m / s.

Answer: the average speed of a skier is Vav = 2.65 m / s.