Answer:
The velocity of the frozen rock at  is -14.711 meters per second.
 is -14.711 meters per second. 
Explanation:
The frozen rock experiments a free fall, which is a type of uniform accelerated motion due to gravity and air viscosity and earth's rotation effect are neglected. In this case, we need to find the final velocity ( ), measured in meters per second, of the frozen rock at given instant and whose kinematic formula is:
), measured in meters per second, of the frozen rock at given instant and whose kinematic formula is:
 (Eq. 1)
 (Eq. 1)
Where:
 - Initial velocity, measured in meters per second.
 - Initial velocity, measured in meters per second.
 - Gravity acceleration, measured in meters per square second.
 - Gravity acceleration, measured in meters per square second. 
 - Time, measured in seconds.
 - Time, measured in seconds.
If we get that  ,
,  and
 and  , then final velocity is:
, then final velocity is:


The velocity of the frozen rock at  is -14.711 meters per second.
 is -14.711 meters per second. 
 
        
             
        
        
        
Answer:
0.4
Explanation:
F-Fr=ma where F is applied force, Fr is friction, m is mass and a is acceleration.
Since the mass is moving with a constant velocity, there's no acceleration hence
 where N is the weight of object and \mu is coefficient of kinetic friction.
 where N is the weight of object and \mu is coefficient of kinetic friction.
![F=\mu N and making [tex]\mu](https://tex.z-dn.net/?f=F%3D%5Cmu%20N%20and%20making%20%5Btex%5D%5Cmu) the subject
 the subject

Substituting F for 8 N and N for 20 N

Therefore, coefficient of kinetic friction is 0.4
 
        
             
        
        
        
Answer:
M₀ = 5i - 4j - k
Explanation:
Using the cross product method, the moment vector(M₀) of a force (F) is about a given point is equal to cross product of the vector A from the point (r) to anywhere on the line of action of the force itself. i.e
M₀ = r x F
From the question,
r = i + j + k
F = 1i + 0j +  5k
Therefore,
M₀ = (i + j + k) x (1i + 0j +  5k)
M₀ = ![\left[\begin{array}{ccc}i&j&k\\1&1&1\\1&0&5\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Di%26j%26k%5C%5C1%261%261%5C%5C1%260%265%5Cend%7Barray%7D%5Cright%5D)
M₀ = i(5 - 0) -j(5 - 1) + k(0 - 1)
M₀ = i(5) - j(4) + k(-1)
M₀ = 5i - 4j - k
Therefore, the moment about the origin O of the force F is 
M₀ = 5i - 4j - k
 
        
             
        
        
        
Plants and animals need nitrogen in order to make proteins. Proteins are essential compounds for healthy growth and fully functioning organisms.
        
             
        
        
        
Answer:

Explanation:
As we know that height of the slide is given as

so time taken by the child to hit the water from the slide is given as

now we will plug all data in it


now we know that the horizontal distance moved by it is given as



now by energy conservation

so height of point A is given as


