Answer:
Explanation:
As we know that the velocity of the object is given as rate of change in its position
so we will have
[tex]v_y = \frac{dh}{dt}[/tex]
now we will have
[tex]v_y = \frac{d}{dt}(3 + 23.5 t - 4.9 t^2)[/tex]
so we will have
[tex]v_y = 23.5 - 9.8 t[/tex]
a)
at t = 2s
[tex]v_y = 3.9 m/s[/tex]
b)
at t = 4 s
[tex]v_y = -15.7 m/s[/tex]