Question

You throw a ball upward from a window at a speed of 1.5 m/s. how fast will it be moving when it hits the sidewalk 2.6 m below?

Answer 1

List out all your variables; 

Initial Velocity (u)= 1.5 ms⁻¹
Final Velocity (v)=? 
Acceleration=9.8 ms⁻¹ (remains constant on free fall problems) 
Displacement (s)=-2.6 m 

v²=u²+2as 
v²=(1.5)²+2(-9.8)(-2.6) 
v²=53.21
v=√53.21
v= 7.2945 ≈ 7.3 ms⁻¹

Hope I helped :)