Asleepy student drops a calculator out of a window that's 20.7\text{ m}20.7 m20, point, 7, start text, space, m, end text off the ground. we can ignore air resistance.
what is the velocity of the calculator after falling for 1.8\,\text s1.8s1, point, 8, start text, s, end text?

Explanation:

You can ignore how high the window actually is, unless the calculator falls further.  You just want to use the formula v_f = v_i + at  Let em know if that doesn't help and I can work you through it.

To check the distance use y = v_i*t + .5at^2.  Would just plug in 0*1.8 + .5(-9.8)1.8^2 = -15.876, so it doesn't fall more than 20.7 m so indeed, you don't have to worry about that.  

Again, let me know if you need further help.

its a 5.5 n

glad that