Answer:
Force pull the child up. With the springs and the weight when you jump. 
 
        
             
        
        
        
Velocity = distance / time 
v = (15*1000)m / (2*60*60)s
v=2.08 m / s
        
                    
             
        
        
        
The answer is:
B. <span>X: Work is done to the system and temperature increases.
Y: Work is done by the system and temperature decreases.</span>
        
                    
             
        
        
        
1).  Calculate how long it takes an object to fall 4,000 m after it's dropped. (Use D = (1/2) (g) (T²) .  D is 4,000 m.  g = 9.8 m/s².  Find T .)
2).  Calculate how far the object will move HORIZONTALLY in that length of time, if it's moving at 75 m/s.  (Distance = (75 m/s) x (time) . )