The position of an object at time t is given by s(t) = -9 - 3t. Find the instantaneous velocity at t = 8 by finding the derivative.
@ganeshie8

Question

The position of an object at time t is given by s(t) = -9 - 3t. Find the instantaneous velocity at t = 8 by finding the derivative.
@ganeshie8

amriju · Answer

do you know how to calculate velocity from the time dependent equation of position ?

ganeshie8 · Answer

$$\large \text{velocity} = \text{(position)}'$$

ganeshie8 · Answer

differentiate s(t) to get the velocity

ganeshie8 · Answer

$$ \large \begin{align} \ 

 s(t) &= -9-3t   \
 v(t) &= s'(t) = ?\


\end{align}
$$

anonymous · Answer

i dont understand that at all... @ganeshie8

ganeshie8 · Answer

differentiate s(t),
what do u get ?

ganeshie8 · Answer

$$ \large \begin{align} \ 

 s(t) &= -9-3t   \
 v(t) &= s'(t) = (-9-3t)'\
&=0-3\
&=-3\
\end{align}
$$

right?

anonymous · Answer

oh i think i understand it now that it is written out! thanks!

ganeshie8 · Answer

good, basically in this problem, velocity doesnt depend on time
the object is goign at constant velcity of -3 m/s or whatever units

ganeshie8 · Answer

so at t=8 also, the velocity would be -3