Question

When to use 5 different epuation of motion s=ut+1/2at² and d=u+a(2n-1)/2

Answer 1

1.  V = u + a t
           When we do not have to look at distance S, but find other quantities

2  V² = u² + 2 a S
           When we do not want to look at time, but at other quantities

3  S = u t +  1/2 a t²
           finding distance traveled by an object with initial velocity u, acceleration a
                 and in time t

4 S = V t - 1/2 a t²
             finding when V is given and not u

5  d or  Sn = u + a(2n - 1)2        OR  Sn = u + (n - 1/2) a
           This is the distance traveled in the nth second only.  time duration is only 1 
           second.