Hey there!
We are given , 
Acceleration, a = -2m/s^2
Initial velocity , u = 15m/s
Time , t = 5 seconds 
We know that ,
V=u+at
Now , final speed ,
V = 15+(-2)(5)
V = 15-10
V = 5 m/s -> final speed
Hope this helps you dear :)
Have a good day <3
        
             
        
        
        
Explanation:
Formula for maximum efficiency of a Carnot refrigerator is as follows.
        ..... (1)
 ..... (1)
And, formula for maximum efficiency of Carnot refrigerator is as follows.
       ...... (2)
 ...... (2)
Now, equating both equations (1) and (2) as follows.
   =
 =  
         
         
                     = 
                     = 
                     = 2.5
Thus, we can conclude that the ratio of heat extracted by the refrigerator ("cooling load") to the heat delivered to the engine ("heating load") is 2.5.
 
        
             
        
        
        
Answer:
225 N
Explanation:
"Below the horizontal" means he's pushing down at an angle.
Draw a free body diagram of the box.  There are three forces: normal force N pushing up, weight force mg pulling down, and the applied force F at an angle θ.
Sum of forces in the y direction:
∑F = ma
N − mg − F sin θ = 0
N = F sin θ + mg
Plug in values:
N = (50 N) (sin 30°) + (20.0 kg) (10 m/s²)
N = 225 N