Answer:
[tex] \boxed{\sf Instantaneous \ velocity \ (v) = -3} [/tex]
Given:
Relation between position of an object at time t is given by:
s(t) = -9 - 3t
To Find:
Instantaneous velocity (v) at t = 8
Step-by-step explanation:
To find instantaneous velocity we will differentiate relation between position of an object at time t by t:
[tex] \sf \implies v = \frac{d}{dt} (s(t))[/tex]
[tex] \sf \implies v = \frac{d}{dt} ( - 9 - 3t)[/tex]
Differentiate the sum term by term and factor out constants:
[tex] \sf \implies v = \frac{d}{dt} ( - 9) - 3 (\frac{d}{dt} (t))[/tex]
The derivative of -9 is zero:
[tex] \sf \implies v = - 3( \frac{d}{dt} (t)) + 0[/tex]
Simplify the expression:
[tex] \sf \implies v = - 3( \frac{d}{dt} (t))[/tex]
The derivative of t is 1:
[tex] \sf \implies v = - 3 \times 1[/tex]
Simplify the expression:
[tex] \sf \implies v = - 3 [/tex]
(As, there is no variable after differentiating the relation between position of an object at time t by t so at time t = 8 is of no use.)
So,
Instantaneous velocity (v) at t = 8 is -3