Answer:
 The magnitude of force must you apply to hold the platform in this position = 888.89 N
Explanation:
Given that :
Workdone (W) = 80.0 J 
length x = 0.180 m
The equation  for this  work done by the spring is expressed as:

Making the spring constant  the subject of the formula; we have:
 the subject of the formula; we have:

Substituting our given values, we have:


The magnitude of the force that must be apply  to the hold platform in this position is given by the formula :


F = 888.89 N
 
        
             
        
        
        
You would have to give it more mechanical energy.
Like, strap a bunch of powerful rockets to one side of the moon, with all of them pointing in the direction that the moon is already moving in its orbit.  Then blast away.
NOTE:  There aren't enough rockets or rocket fuel on Earth to make a difference, even if you used ALL of them.  The mass of the moon is about 
<em>73,476,730,900,000,000,000,000 kilograms</em>
(rounded to the nearest hundred trillion kilograms.)
That's a lot. 
 
        
                    
             
        
        
        
The contact force is indeed caused by "Contact". 
Air resistance is basically a type of friction, which is apparently present providing two object contact.
The rest selections are all interaction force, which is not necessarily caused by contact.
        
                    
             
        
        
        
Answer:
Option A
Explanation:
Mechanical waves requires some medium to travel through. They travel faster in the dense medium as compared to a free medium. 
The speed of a mechanical wave is fastest in the solid medium and the slowest in the gaseous medium. Hence, as the wave traverses from gaseous medium to the solid medium, its speed increases. 
Thus, option A is correct
 
        
             
        
        
        
Answer: 
Uranus, Pluto, Neptune, Saturn , Jupiter, mars, Venus ,mercury and sun