A 70.0-kg person throws a 0.0430-kg snowball forward with a ground speed of 32.0 m/s. A second person, with a mass of 58.5 kg, catches the snowball. Both people are on skates. The first person is initially moving forward with a speed of 3.30 m/s, and the second person is initially at rest. What are the velocities of the two people after the snowball is exchanged

The velocities of the skaters are and , respectively.

Explanation:

Each skater is not under the influence of external forces during process, so that Principle of Momentum Conservation can be used on each skater:

First skater

(1)

Second skater

(2)

Where:

- Mass of the first skater, in kilograms.

- Mass of the second skater, in kilograms.

- Initial velocity of the first skater, in meters per second.

- Final velocity of the first skater, in meters per second.

- Launch velocity of the meter, in meters per second.

- Final velocity of the second skater, in meters per second.

If we know that , , , and , then the velocities of the two people after the snowball is exchanged is:

By (1):

By (2):

v=ir = 3x15 =45 v

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =