Kinetic energy is related to velocity by: 
KE = (1/2)mv^2 
solve for mass m
10 = (1/2)m(10)^2
10 = (1/2)m(100)
10= 50m
10/50 = m 
1/5 = m 
at 20 km/hr
KE = (1/2)(1/5)(20)^2
KE = (1/10)(400)
KE = 40 J 
        
             
        
        
        
Answer:
Approximately  .
.
Explanation:
Cathode is where reduction takes place and anode is where oxidation takes place. The potential of a electrochemical reaction ( ) is equal to
) is equal to 
 .
.
There are two half-reactions in this question.  and
 and  . Either could be the cathode (while the other acts as the anode.) However, for the reaction to be spontaneous, the value of
. Either could be the cathode (while the other acts as the anode.) However, for the reaction to be spontaneous, the value of  should be positive.
 should be positive. 
In this case,  is positive only if
 is positive only if  is the reaction takes place at the cathode. The net reaction would be
 is the reaction takes place at the cathode. The net reaction would be
 .
.
Its cell potential would be equal to  .
.
The maximum amount of electrical energy possible (under standard conditions) is equal to the free energy of this reaction:
 ,
, 
where
 is the number moles of electrons transferred for each mole of the reaction. In this case the value of is the number moles of electrons transferred for each mole of the reaction. In this case the value of is is as in the half-reactions. as in the half-reactions.
 is Faraday's Constant (approximately is Faraday's Constant (approximately .) .)
 .
.
 
        
             
        
        
        
Answer:
The box displacement after 6 seconds is 66 meters. 
Explanation:
Let suppose that velocity given in statement represents the initial velocity of the box and, likewise, the box accelerates at constant rate. Then, the displacement of the object ( ), in meters, can be determined by the following expression:
), in meters, can be determined by the following expression:
 (1)
 (1)
Where:
 - Initial velocity, in meters per second.
 - Initial velocity, in meters per second.
 - Time, in seconds.
 - Time, in seconds.
 - Acceleration, in meters per square second.
 - Acceleration, in meters per square second.
If we know that  ,
,  and
 and  , then the box displacement after 6 seconds is:
, then the box displacement after 6 seconds is:

The box displacement after 6 seconds is 66 meters. 
 
        
             
        
        
        
Answer:
The speed after being pulled is 2.4123m/s
Explanation:
The work realize by the tension and the friction is equal to the change in the kinetic energy, so:
 (1)
 (1)
Where:

Because the work made by any force is equal to the multiplication of the force, the displacement and the cosine of the angle between them.
Additionally, the kinetic energy is equal to  , so if the initial velocity
, so if the initial velocity  is equal to zero, the initial kinetic energy
 is equal to zero, the initial kinetic energy  is equal to zero.
 is equal to zero.
Then, replacing the values on the equation and solving for  , we get:
, we get:


So, the speed after being pulled 3.2m is 2.4123 m/s
 
        
             
        
        
        
Answer: m∠P ≈ 46,42°
because using the law of sines in ΔPQR
=> sin 75°/ 4 = sin P/3
so ur friend is wrong due to confusion between edges
+) we have: sin 75°/4 = sin P/3
=> sin P = sin 75°/4 . 3 = (3√6 + 3√2)/16
=> m∠P ≈ 46,42°
Explanation: