Balancing.
When the same force is applied from both sides,the forces cancel out each other.
        
             
        
        
        
D=m÷v
so density would be 57.9 ÷ 3 = 19.3 g/cm³
        
                    
             
        
        
        
Answer:
8:P.E,9:gaining K.E,10:P.E,11:gaining K.E.
Explanation:
it gained potential energy at 8 because it was at its maximum height,and since potential energy is the energy that u posses due to ur height,thats the energy it possesed on the spot 8.as you can see on spot 9 its moving down so as its moving down,it gains kinetic energy,since its an energy possesed by a body due to its motion/movement,thats what it gained at spot 9, it gsained kineti energy because of its movement.and at 10 agian it would gain potential energy ecause of height and on point 11 as its heading upwards it gains kinetic energy because of movement. 
 
        
             
        
        
        
Answer:
its 1 
Explanation:
Several factors can increase the rate of a chemical reaction. In general, anything that increases the number of collisions between particles will increase the reaction rate, and anything that decreases the number of collisions between particles will decrease the chemical reaction rate. 
Hope this helps? :))