Percentage for which columns btw if its something as easy as percentage for 4/5... you divid 4/5= .80 then.... .80*100= 80%
Lets calculate the initial speed of the block. We know that kinetic energy is given by:

Solving for v₀:

If the speed after it hits a wall is half its original speed then:
v = v₀/2 = 2 m/s / 2 = 1 m/s
Then the kinetic energy at this point is:

The inetic energy of this object at this point is 0.5 J.
The average time that it takes for the car to travel the first 0.25m is 2.23 s
The average time that it takes for the car to travel the first 0.25 m is given by:

The average time to travel just between 0.25 m and 0.50 m is 0.90 s
First of all, we need to calculate the time the car takes in each trial to travel between 0.25 m and 0.50 m:

Then, the average time can be calculated as

Given the time taken to travel the second 0.25 m section, the velocity would be 0.28 m/s
The velocity of the car while travelling the second 0.25 m section is equal to the distance covered (0.25 m) divided by the average time (0.90 s):

Complete Question
Planet D has a semi-major axis = 60 AU and an orbital period of 18.164 days. A piece of rocky debris in space has a semi major axis of 45.0 AU. What is its orbital period?
Answer:
The value is
Explanation:
From the question we are told that
The semi - major axis of the rocky debris 
The semi - major axis of Planet D is 
The orbital period of planet D is 
Generally from Kepler third law

Here T is the orbital period while a is the semi major axis
So

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=> ![T_R = 18.164 * [\frac{ 45}{60} ]^{\frac{3}{2} }](https://tex.z-dn.net/?f=T_R%20%20%3D%2018.164%20%20%2A%20%20%5B%5Cfrac%7B%2045%7D%7B60%7D%20%5D%5E%7B%5Cfrac%7B3%7D%7B2%7D%20%7D)
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