Tom N. answered • 08/25/19

Strong proficiency in elementary and advanced mathematics

Let s= v_{0}t -gt^{2}/2 where g=9.8 m/sec^{2} and v_{0} is the initial velocity. The velocity at the maximum height is 0 so v= v_{0} -gt =0 and v_{0} =gt or t= v_{0}/g for the time to reach 1.3m So the equation becomes 1.3 = v_{0}(v_{0}/g) -4.9(v_{0}^{2}/g^{2}) or 1.3 = v_{0}^{2}/9.8 -v_{0}^{2}(4.9/9.8^{2}) = v_{0}^{2}/9.8( 1-1/4.9•9.8) and so 1.3•9.8 = v_{0}^{2}(1-1/4.9) = v_{0}^{2}(3.9/4.9). This gives v_{0}^{2}= 16 and v_{0} =4 m/sec.