Question

solve by differentiation calculus.Find velocity at 2sec​

Answer 1

$s = 8.5 + 2.5 {t}^{2} \\ \frac{ds}{dt} = 0 + 5t \\ v = 5t \\ so \: wen \: t = 2sec \\ then \\ v = 10 \frac{m}{s}$

Answer 2

diff t= 2 × 2.5t because d/dt(constant)=0

S = 5 t

S = 5(2)=10.