Answer:
1000 N
Explanation:
First, we need to find the deceleration of the running back, which is given by:

where
v = 0 is his final velocity
u = 5 m/s is his initial velocity
t = 0.5 s is the time taken
Substituting, we have

And now we can calculate the force exerted on the running back, by using Newton's second law:

so, the magnitude of the force is 1000 N.
 
        
                    
             
        
        
        
Answer:
✓ A cyclone device accumulates fine particulates from the air by making a dirty air stream flow in a spiral path inside a  cylindrical chamber. 
✘ It consists of several long and narrow fabric filter bags suspended upside-down in a large  enclosure. 
✓ When dirty air enters the chamber, the larger particulates strike the chamber wall and fall into a conical dust  hopper at the bottom. 
✘ Fans blow dirt-filled air upward from the bottom of the enclosure, trapping dirt particles inside the  filter bags and releasing clean air from the top. 
✓ The top of the chamber has an outlet that lets out cleaned air.
Basically, any of these choices that have the word "filter" are wrong. The point of the cyclone device is to separate the particles without the use of filters. You can tell the right answers based on the picture attached below.
 
        
                    
             
        
        
        
Answer:
0.144 kg of water
Explanation:
From Raoult's law,
Mole fraction of solvent = vapor pressure of solution ÷ vapor pressure of solvent = 423 mmHg ÷ 528.8 mmHg = 0.8
Let the moles of solvent (water) be y
Moles of solute (C3H8O3) = 2 mole
Total moles of solution = moles of solvent + moles of solute = (y + 2) mol
Mole fraction of solvent = moles of solvent/total moles of solution
0.8 = y/(y + 2)
y = 0.8(y + 2)
y = 0.8y + 1.6
y - 0.8y = 1.6
0.2y = 1.6
y = 1.6/0.2 = 8
Moles of solvent (water) = 8 mol
Mass of water = moles of water × MW = 8 mol × 18 g/mol = 144 g = 144/1000 = 0.144 kg