Newton's first law of motion states that an object at rest tends to stay at rest, while an object in motion tends to stay in motion unless an external force acts upon it. This law appears in basketball when the player is shooting the ball. When the player is holding the ball, the ball is at rest but when a player shoots the ball, they use force to throw the ball in the hoop.
Has an Environmental Impact. Perhaps the largest disadvantage of hydroelectric energy is the impact it can have on the environment.
It Displaces People.
It's Expensive.
There are Limited Reservoirs.
There are Droughts.
It's Not Always Safe
Answer:
The duration is ![T =72 \ years /tex]Explanation:From the question we are told that The distance is [tex]D = 35 \ light-years = 35 * 9.46 *10^{15} = 3.311 *10^{17} \ m](https://tex.z-dn.net/?f=T%20%20%3D72%20%5C%20%20years%20%2Ftex%5D%3C%2Fp%3E%3Cp%3EExplanation%3A%3C%2Fp%3E%3Cp%3EFrom%20the%20question%20we%20are%20told%20that%20%3C%2Fp%3E%3Cp%3E%20%20%20%20The%20%20distance%20is%20%20%5Btex%5DD%20%20%3D%20%2035%20%5C%20light-years%20%3D%2035%20%2A%20%209.46%20%2A10%5E%7B15%7D%20%3D%203.311%20%2A10%5E%7B17%7D%20%5C%20%20m%20)
Generally the time it would take for the message to get the the other civilization is mathematically represented as

Here c is the speed of light with the value 
=> 
=> 
converting to years



Now the total time taken is mathematically represented as

=> 
=> [tex]T =72 \ years /tex]
To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.
Gravitational potential energy can be defined as

As M=m, then

Where,
m = Mass
G =Gravitational Universal Constant
R = Distance /Radius
PART A) As half its initial value is u'=2u, then



Therefore replacing we have that,

Re-arrange to find v,



Therefore the velocity when the separation has decreased to one-half its initial value is 816m/s
PART B) With a final separation distance of 2r, we have that

Therefore




Therefore the velocity when they are about to collide is 