Answer:
D
Explanation:
One of the factors of increasing the rate of a reaction is increasing concentration. Therefore adding more people increases the number of people on the dance floor , therefore increasing the concentration increases the rate of reaction.
 
        
             
        
        
        
Answer:
176,000 N
Explanation:
Newton's second law:
∑F = ma
F = (4 × 40,000 kg) (1.1 m/s²)
F = 176,000 N
 
        
                    
             
        
        
        
Answer:
1min since there is no gravity on the moon so it will take time to drop on the moon.
Explanation:
 
        
             
        
        
        
(a) 0.249 (24.9 %)
The maximum efficiency of a heat engine is given by

where
Tc is the low-temperature reservoir
Th is the high-temperature reservoir
For the engine in this problem,


Therefore the maximum efficiency is

(b-c) 0.221 (22.1 %)
The second steam engine operates using the exhaust of the first. So we have:
 is the high-temperature reservoir
 is the high-temperature reservoir
 is the low-temperature reservoir
 is the low-temperature reservoir
If we apply again the formula of the efficiency

The maximum efficiency of the second engine is

 
        
             
        
        
        
Answer:
30Km/h
Explanation:
acceleration is the change of speed in a given time so when we substract the accelerations we can know how much the car goes per an hour