Any body falling in an airless space near the Earth’s surface travels about 5 m in the first second of motion

Any body falling in an airless space near the Earth’s surface travels about 5 m in the first second of motion, and about 15 m in the second. Calculate the average speed of the body in two seconds of motion.

Given:

S1 = 5 meters – the path taken by a freely falling body in 1 second;

S2 = 15 meters – the path taken by a freely falling body in the second second;

t = 2 seconds – time span.

It is required to determine the average speed of the body Vav (m / s) over time t.

Let’s find the common path that the body will cover in 2 seconds:

S = S1 + S2 = 5 + 15 = 20 meters.

Then the average speed will be:

Vav = S / t = 20/2 = 10 m / s.

Answer: the average speed of a freely falling body in the first 2 seconds is 10 m / s.