Aparticle moves along a straight line and its position at time t is given by s(t)=2t3−27t2+84t where s is measured in feet and t in seconds. a) find the velocity (in ft/sec) of the particle at time t=0: 84 b) the particle stops moving twice, once when t=a and again when t=b where a

a)

b)

c)

d) Δs=4428ft

Explanation:

From the exercise we know the equation of position

a) To calculate the velocity we need to derivate the equation of position

So, v(0) is:

b) To find the two times where the particle stops A and B we need to solve the quadratic equation:

Solving for t

and

c)

d) Δs=4428ft-0ft=4428ft

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6