Answer:
The two skaters will move with a common speed of 1.19 m/s.
Explanation:
Given that,
Mass of Alex, 
Initial velocity of Alex, 
Mass of Barbara, 
Initial velocity of Barbara, 
After the collision, the two skaters move together at a common velocity. Let V is the common velocity. Using the conservation of momentum as :

Magnitude of final velocity:

So, the two skaters will move with a common speed of 1.19 m/s.
The speed of the cart after 3 seconds of Low fan speed is equal to 54 cm/s.
<h3>How to calculate the speed?</h3>
Mathematically, speed can be calculated by using this formula;
Speed = distance/time
At Low fan speed after 3 seconds, the distance covered is 162 cm:
Speed = 162/3
Speed = 54 cm/s.
At Medium fan speed after 5 seconds, the distance covered is 600 cm:
Speed = 600/5
Speed = 120 cm/s.
At High fan speed after 2 seconds, the distance covered is 128 cm:
Speed = 128/2
Speed = 64 cm/s.
Read more on speed here: brainly.com/question/17350470
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The answer is 7 electrons. We know that Carbon has 6 electrons, so we could see that there is the charge that is -1, meaning there has to be one more electron than proton because that means it's gained an electron of -1 charge. Therefore 7 electrons to 6 protons.