Solutions

In[1]:=

(*1*)Clear[y, t] ; g = -9.81 ; y[t_] = y[t]/.Part[DSolve[{y''[t] g,  ... , y '[0] 10}, y[t], t], 1] ; Print["y[t] = ", y[t]] Clear[g] ;

y[t] = 10 t - 4.905 t^2

The highest point is where the speed of the ball is zero.

In[5]:=

(*2*)v[t_] = D[y[t], t] ; Print[y    = , y[t]/.Part[Solve[v[t] 0, t] ...            max                                                                             y = 0

y    = 5.09684 m  max

t      = 2.03874 s  y = 0


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