Answer: 37.981 m/s
Explanation:
This situation is related to projectile motion or parabolic motion, in which the travel of the ball has two components: <u>x-component</u> and <u>y-component.</u> Being their main equations as follows:
<u>x-component:
</u>
 (1)
   (1)
Where:
 is the point where the ball strikes ground horizontally
 is the point where the ball strikes ground horizontally
 is the ball's initial speed
 is the ball's initial speed
 because we are told the ball is thrown horizontally
 because we are told the ball is thrown horizontally
 is the time since the ball is thrown until it hits the ground
 is the time since the ball is thrown until it hits the ground
<u>y-component:
</u>
 (2)
   (2)
Where:
 is the initial height of the ball
  is the initial height of the ball
 is the final height of the ball (when it finally hits the ground)
  is the final height of the ball (when it finally hits the ground)
 is the acceleration due gravity
  is the acceleration due gravity
Knowing this, let's start by finding  from (2):
 from (2):
<u></u>
 (3)
   (3)
 
   
 (4)
   (4)
 (5)
   (5)
 (6)
   (6)
Then, we have to substitute (6) in (1):
 (7)
   (7)
And find  :
:
 (8)
   (8)
 (9)
   (9)
 (10)
   (10)
On the other hand, since we are dealing with constant acceleration (due gravity) we can use the following equation to find the value of the ball's final velocity  :
:
 (11)
 (11)
 (12)
 (12)
 (13) This is the ball's final velocity, and the negative sign indicates its direction is downwards.
 (13) This is the ball's final velocity, and the negative sign indicates its direction is downwards.
However, we were asked to find the <u>ball's final speed</u>, which is the module of the ball's final vleocity vector. This module is always positive, hence the speed of the ball just before it strikes the ground is 37.981 m/s (positive).
 
        
             
        
        
        
Answer:
Ep = 3924 [J]
Explanation:
To calculate this value we must use the definition of potential energy which tells us that it is the product of mass by the acceleration of gravity by height.

where:
Ep = potential energy [J] (units of Joules)
m = mass = 40 [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 10 [m]
![E_{p} =40*9.81*10\\E_{p} = 3924 [J]](https://tex.z-dn.net/?f=E_%7Bp%7D%20%3D40%2A9.81%2A10%5C%5CE_%7Bp%7D%20%3D%203924%20%5BJ%5D)
 
        
             
        
        
        
The Speed In Kilometers per year is 63.072.
        
             
        
        
        
Then everyone would fall off the surface
        
                    
             
        
        
        
Both a molten metallic core and reasonably fast rotation.