Answer:
So the ratio will be 
Explanation:
We have given heat engine absorbs 450 joule from high temperature reservoir 
So 
As the heat engine expels 290 j 
So work done W = 290 J 
We know that efficiency 
It is given that efficiency of the engine only 55 % of Carnot engine 
So efficiency of Carnot engine 
Efficiency of Carnot engine is 


 
 
        
                    
             
        
        
        
The launch velocity of the marble launcher is 34.65 m/s
Given that the launch velocity of marble launcher, launches a 25g marble to a distance of 73 cm (0.73 m) and the marble roll up to 6.2 meters before stopping. The launch height is 20 cm (0.2 m).
The time for landing can be calculated by the second equation of motion formula:
h = ut +  g
g
Let u = 0
0.2 = 0×t +  × 9.8 ×
 × 9.8 × 
 =
 = 
 = 0.04
 = 0.04
t = 0.2s
Now, the launch velocity of the marble launcher can be calculated by:
Speed = Distance / Time
Speed = 
Speed = 
Speed = 34.65 m/s
Therefore, the launch velocity of the marble launcher is 34.65 m/s
Know more about Launch velocity: -brainly.com/question/18883779
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Answer:
3 fans per 15 A circuit
Explanation:
From the question and the data given, the light load let fan would have been 
(60 * 4)/120 = 240/120 = 2 A.
Next, we add the current of the fan motor to it, so,
2 A + 1.8 A = 3.8 A.
Since the devices are continuos duty and the circuit current must be limited to 80%, then the Breaker load max would be
0.8 * 15 A = 12 A.
Now, we can get the number if fans, which will be 
12 A/ 3.8 A = 3.16 fans, or approximately, 3 fans per 15 A circuit. 
 
        
             
        
        
        
Answer:
ρ = M / V = 2 g / .5 cm^3 = 4 g/cm^3