So, the speed of the ball after 2 seconds after free fall is <u>20 m/s</u>.
<h3>Introduction</h3>
Hi ! I'm Deva from Brainly Indonesia. In this material, we can call this event "Free Fall Motion". There are two conditions for free fall motion, namely falling (from top to bottom) and free (without initial velocity). Because the question only asks for the final velocity of the ball, in fact, we may use the formula for the relationship between acceleration and change in velocity and time. In general, this relationship can be expressed in the following equation :

With the following conditions :
- a = acceleration (m/s²)
= speed after some time (m/s)
= initial speed (m/s)- t = interval of time (s)
<h3>Problem Solving</h3>
We know that :
- a = acceleration = 9,8 m/s² >> because the acceleration of a falling object is following the acceleration of gravity (g).
= initial speed = 0 m/s >> the keyword is free fall- t = interval of time = 2 s
What was asked :
= speed after some time = ... m/s
Step by step :




So, the speed of the ball after 2 seconds after free fall is 20 m/s.
Answer:

Explanation:
The angular speed is defined as the angle traveled in one revolution over the time taken to travel it, that is, the period. Therefore, it is given by:

The angular frequency of the simple harmonic motion of the mass-spring system is defined as follows:

Here, k is the spring's constant and m is the mass of the body attached to the spring. Solving for k:

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Answer:
Because the mass of electrons and protons is very small
Explanation:
The gravitational force exerted between two objects is given by:

where
is the gravitational constant
m1 and m2 are the masses of the two objects
r is the distance between the two objects
The mass of a proton and of an electron is very small, so the gravitational force involved in case of such particles is very weak. Let's calculate for example the gravitational attraction between one proton and one electron at a distance of r = 1 m. We have:
- Proton mass: 
- Electron mass: 
So, the gravitational force between the two particles is:

Which is a very weak force.
By comparison, let's calculate instead the electromagnetic force between a proton and an electron (both having a charge of
) still separated by a distance of r = 1 m. We have:

Which we see is much stronger than the gravitational force (almost by a factor 
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