Answer:
j
Explanation:
x = 4 t^2 - 2 t - 4.5
Position at t = 3 s
x = 4 (3)^2 - 2 (3) - 4.5 = 25.5 m
Velocity at t = 3 s
v = dx / dt = 8 t - 2
v ( t = 3 s) = 8 x 3 - 2 = 22 m/s
Acceleration at t = 3 s
a = dv / dt = 8
a ( t = 3 s ) = 8 m/s^2
When is the velocity = 0
v = 0
8 t - 2 = 0
t = 0.25 second
When is the position = 0
x = 0
4 t^2 - 2 t - 4.5 = 0

t = 1.4 second
Power cords are conductors and are covered by insulators. If they were not, then it would be easy to create a short-circuit. It would also be not safe, as a person touching the bare wires would be electricuted.
use the formula
v= u+ at
v is final velocity , u is initial velocity , a is acceleration and t is time
put the values
20 = 0+ a×5
a = 4 m/s²