Answer
The instantaneous velocity at t = 1 second is 5.2 m/s
Work Step by Step
time interval [1,1.01]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1.01)-(4.9\times{1.01^{2}})]-[(15\times1)-(4.9\times{1^{2}})]}{1.01-1}$ = $5.151$
time interval [1,1.001]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1.001)-(4.9\times{1.001^{2}})]-[(15\times1)-(4.9\times{1^{2}})]}{1.001-1}$ = $5.1951$
time interval [1,1.0001]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1.0001)-(4.9\times{1.0001^{2}})]-[(15\times1)-(4.9\times{1^{2}})]}{1.001-1}$ = $5.1995$
time interval [0.99,1]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1)-(4.9\times{1^{2}})]-[(15\times0.99)-(4.9\times{0.99^{2}})]}{1-0.99}$ = $5.249$
time interval [0.999,1]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1)-(4.9\times{1^{2}})]-[(15\times0.999)-(4.9\times{0.999^{2}})]}{1-0.999}$ = $5.2049$
time interval [0.9999,1]
$\frac{Δh}{Δt}$ = $\frac{[(15\times1)-(4.9\times{1^{2}})]-[(15\times0.9999)-(4.9\times{0.9999^{2}})]}{1-0.9999}$ = $5.2005$
The instantaneous velocity at t = 1 second is 5.2 m/s
