Answer:
The maximum velocity the mass can have if the string is not to break = 29.05 m/s
Explanation:
The force balance in the mass:
The tension in the string must always be equal to the force keeping the mass in horizontal circular motion. 
The force keeping the mass in circular motion is given by
F = mv²/r
m = mass of body = 0.4 kg
v = speed of the body in circular motion
r = radius of the circular motion = 0.75 m
Maximum tension the string can withstand will correspond to the maximum velocity of the body in horizontal circular motion
T = F = mv²/r
450 = (0.4)(v²)/(0.75)
v² = 450×0.75/0.4 = 843.75
v = 29.05 m/s
 
        
                    
             
        
        
        
Explanation:
Formula for angle subtended at the center of the circular arc is as follows.
            
where,   S = length of the rod
               r = radius
Putting the given values into the above formula as follows.      
                 
                              = 
                              = 
                              = 
Now, we will calculate the charge density as follows.
                  
                             = 
                             = 
Now, at the center of arc we will calculate the electric field as follows.
                  E = 
                      = 
                       = 34.08 N/C
Thus, we can conclude that the magnitude of the electric eld at the center of curvature of the arc is 34.08 N/C.
 
        
             
        
        
        
W = mg
Weight on Earth = 50 x 9.8
                          = 490 N
Weight on Mars = 50 x 3.7
                          = 185 N 
        
                    
             
        
        
        
Space debris that enters earths atmosphere
        
             
        
        
        
Answer:
Vertical velocity decreases.
Explanation:
The motion of the ball is a projectile ball, which consists of two independent motions:
- a horizontal motion, with constant velocity
- a vertical motion, with constant acceleration g=9.8 m/s^2 towards the ground
In the vertical motion, there is a constant acceleration directed downward: this means that the vertical velocity decreases as the ball goes higher. In fact, it decreases following the equation

And it decreases until the ball reaches its maximum height, then it starts increasing again.