<u>Answer</u>: The mass of the object is 25kg.
The given question deals with Newton's second law of motion and its applications.
<u>Explanation:</u> Given force, F=500N
                                  acceleration, a=20 m/
   From Newton's 2nd law of motion , we have 
                              F=ma where m=mass of the object 
                          ⇒500=m×20
                          ⇒m=500/20=25
                  ∴ Mass of the object is 25 kg .
<u> </u><u>Reference Link: </u>brainly.com/question/1141170
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Eris is slightly more massive than Pluto. However, both of them are smaller than Earth's Moon.
This should conclude that Eris is a dwarf planet.
        
                    
             
        
        
        
Answer:
1)Fuel Sourcing
2)Power Generation
Explanation:
1)Fuel Sourcing
: Fossil fuels must be located, excavated and transported before they can be used. These processes are invasive and detrimental to the land through side effects such as erosion as well as ecological and geologic instability. Then the deposit or well is depleted. Energy from the sun is infinite and free. It can be harnessed and turned into power anywhere a solar panel can be mounted.
2)Power Generation:
 Fossil fuels must be burned to produce electricity. Burning them creates unwanted byproducts that can create air and water pollution and release huge amounts of greenhouse gasses into the atmosphere.
 
        
                    
             
        
        
        
The motion of the ball on the vertical axis is an accelerated motion, with acceleration 

The following relationship holds for an uniformly accelerated motion:

where S is the distance covered, vf the final velocity and vi the initial velocity.
If we take the moment the ball reaches the maximum height (let's call this height h), then at this point of the motion the vertical velocity is zero:

So we can rewrite the equation as

from which we can isolate h

 (1)
Now let's assume that 

 is the initial velocity of the first ball. The second ball has an initial velocity that is twice the one of the first ball: 

. So the maximum height of the second ball is

 (2)
Which is 4 times the height we found in (1). Therefore, the maximum height of ball 2 is 4 times the maximum height of ball 1.
 
        
        
        
Answer:
The correct option is D
Explanation:
This question is incomplete because of the absence of the setup which as been attached below. The setup shows/determines/tests the friction of wood (which is a block material), since Jerry wants to test the friction between different types of materials, he will have to replace the wooden block with another type of block material of choice so as to determine the friction of that also.
In order to have a comprehensive experiment, Jerry can use 4-5 different types of block material in the course of the experiment.