Answer:
a. Vf = 39.24 [m/s]
b. Vf = 31.24 [m/s]
c. Vf = 47.24 [m/s].
Explanation:
To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (when the rock is dropped)
g = gravitational acceleration = 9.81 [m/s²]
t = time = 4 [s]
a.
![v_{f}=0+9.81*4\\v_{f}= 39.24 [m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D0%2B9.81%2A4%5C%5Cv_%7Bf%7D%3D%2039.24%20%5Bm%2Fs%5D)
b.
In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.
![v_{f}=8-(9.81*4)\\v_{f}=-31.24[m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D8-%289.81%2A4%29%5C%5Cv_%7Bf%7D%3D-31.24%5Bm%2Fs%5D)
The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.
c.
![v_{f}=8+(9.81*4)\\v_{f}=47.24[m/s]](https://tex.z-dn.net/?f=v_%7Bf%7D%3D8%2B%289.81%2A4%29%5C%5Cv_%7Bf%7D%3D47.24%5Bm%2Fs%5D)
Answer:
0 m/s.
Explanation:
When an object is shot up into the air the only force acting on it is gravity while neglecting wind. As the gravity is acting on the object it keeps decelerating till its velocity becomes 0 after which it can go no further. The maximum height of the object is at this point.
So, at its maximum height the velocity of the puck will be zero.
<em><u>Here your answer</u></em>
Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.
<em><u>hope it helps ☺️✌️</u></em>
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