Answer:
a) t=1s
y = 10.1m
v=5.2m/s
b) t=1.5s
y =11.475 m
v=0.3m/s
c) t=2s
y =10.4 m
v=-4.6m/s  (The minus sign (-) indicates that the ball is already going down)
Explanation:
Conceptual analysis
We apply the free fall formula for position (y) and speed (v) at any time (t).
As gravity opposes movement the sign in the equations is negative.:  
y = vi*t - ½ g*t2 Equation 1
v=vit-g*t  Equation 2
y: The vertical distance the ball moves at time t  
vi: Initial speed
g= acceleration due to gravity
v= Speed the ball moves at time t  
Known information
We know the following data:
Vi=15 m / s

t=1s ,1.5s,2s
Development of problem
We replace t in the equations (1) and (2)  
a) t=1s
 =15-4.9=10.1m
=15-4.9=10.1m
v=15-9.8*1 =15-9.8 =5.2m/s
b) t=1.5s
 =22.5-11.025=11.475 m
=22.5-11.025=11.475 m
v=15-9.8*1.5 =15-14.7=0.3m/s
c) t=2s
 = 30-19.6=10.4 m
= 30-19.6=10.4 m
v=15-9.8*2 =15-19.6=-4.6m/s  (The minus sign (-) indicates that the ball is already going down)
 
        
             
        
        
        
True ! Attending the funeral of a foreign leader IS fulfilling the role of head of state.
        
             
        
        
        
I agree with the other comment
        
             
        
        
        
It increases confidence because the more times you conduct the same experiment over and over should either prove your hypothesis right and wrong and eliminate any random occurrences that might affect your results.
        
                    
             
        
        
        
The answer would be a frog!