#h=y_i+v_i*t*sin alpha-1/2*g*t^2#
#y_i:"height of building"#
#v_i="initial velocity"#
#alpha="angle"#
#sin 25=0.423#
#t:"time"#
#g:9.81" "m/s^2#
#0=y_i+15*3*0.423-1/2*9.81*3^2#
#"we have written h=0 because object has fallen"#
#0=y_i+19.035-44.145#
#0=y_i-25.11#
#y_i=25.11 " "m#