the position function of a particle is given by

Question

s=t^3–4t^2–7t t>=0

where s is measured in meters and t in seconds. When does the particle reach a velocity of 10 m/s?

Answer 1

Take the derivative:

v=3t^2 -8t -7

put v=10 and rearrange it to have a quadratic in standard format, solve the quadratic with the quadratic formula.

Answer 2

i got 1.39 and -4.06 but i still got it wrong