Answer:
6.9
7.-5
8.-10
Step-by-step explanation:
DATES: The rule amendments will become effective October 29, 1999. Section IV of this release contains information on compliance dates.
To Find :
Position vector at time
and
.
Solution :
r (t) = 2 (t −7)i + 12t j
Putting t = 5 s and t = 8 s, we get :
r(5) = 2( -2 )i + 60j
r(5) = -4i + 60j
r(8) = 2i + 96j
Now, to find speed differentiating the r(t) w.r.t t :

Hence, this is the required solution.
Step 1) distribute the 17: -16+119w-204
Step 2) combine like terms: 119w-220
ANSWER: 119w-220