Answer:
[tex]-14.7 \frac{m}{s} \hat{j}[/tex].
Explanation:
The kinematic equation for velocity [tex]\vec{V}[/tex] with constant acceleration [tex]\vec{a}[/tex] at time t is :
[tex]\vec{V}(t) \ = \ \vec{V}_0 \ + \ \vec{a} \ t[/tex].
Assuming that the initial velocity is zero
[tex]\vec{V}_0 = 0[/tex]
and knowing that the gravitational acceleration is
[tex]\vec{a} = - 9.8 \frac{m}{s^2} \hat{j}[/tex]
The equation is
[tex]\vec{V}(t) \ = - 9.8 \frac{m}{s^2} \ t \ \hat{j}[/tex].
After 1.5 seconds, this gives us
[tex]\vec{V}(t) \ = - 9.8 \frac{m}{s^2} \ t \ \hat{j}[/tex].
[tex]\vec{V}(1.5 s) \ = - 9.8 \frac{m}{s^2} \ 1.5 s \ \hat{j} = -14.7 \frac{m}{s} \hat{j}[/tex].
And this is the velocity at impact.
