Given data
*The given height of the building h = 56 m
*The distance from the base is d = 45 m
*The value of the acceleration due to gravity is g = 9.8 m/s^2
The formula for the time taken by the lemming is given as
[tex]t=\sqrt[]{\frac{2h}{g}}[/tex]Substitute the known values in the above expression as
[tex]\begin{gathered} t=\sqrt[]{\frac{2\times56}{9.8}} \\ =3.38\text{ s} \end{gathered}[/tex]The formula for the lemming's initial speed is given as
[tex]v=\frac{d}{t}[/tex]Substitute the known values in the above expression as
[tex]\begin{gathered} v=\frac{45}{3.38} \\ =13.3\text{ m/s} \end{gathered}[/tex]Hence, the lemming's initial speed is v = 13.3 m/s