Question
Topic-(a)-4.3: Rates of Change in Applied Contexts Other Than Motion,
Topic-(b)-4.2: Connecting Position, Velocity, and Acceleration of Functions Using Derivatives.
Topic-(c)-4.2: Straight-Line Motion: Connecting Position, Velocity, and Acceleration.
Topic-(d)-8.2: Connecting Position, Velocity, and Acceleration of Functions Using Integrals
A particle moves along the x-axis so that its velocity at time t ≥ 0 is given by v ( t) = ln
(a) There is one time,
, in the interval 0 < t < 2 when the particle is at rest (not moving). Find
. For 0 < t <
, is the particle moving to the right or to the left? Give a reason for your answer.
(b) Find the acceleration of the particle at time t = 1.5. Show the setup for your calculations. Is the speed of the particle increasing or decreasing at time t = 1.5 ? Explain your reasoning.
(c) The position of the particle at time t is x (t ), and its position at time t = 1 is x(1) = −3. Find the position of the particle at time t = 4. Show the setup for your calculations.
(d) Find the total distance traveled by the particle over the interval
. Show the setup for your calculations.
▶️Answer/Explanation
Ans:
2(a) There is one time, t =
, in the interval 0 < 7 < 2 when the particle is at rest (not moving). Find
.For 0 <t <
, is the particle moving to the right or to the left? Give a reason for your answer.
v(t) =0
t = 1.425610
Therefore, the particle is at rest (not moving) at
, = 1.426 (or 1.425).
For
. Therefore, the particle is moving to the right on that interval.
2(b) Find the acceleration of the particle at time t = 1.5. Show the setup for your calculations. Is the speed of the particle increasing or decreasing at time t = 1.5 ? Explain your reasoning.
a(1.5) =v'(1.5) = -1
The acceleration of the particle at time t = 1.5 is —1 (or —0.999).
v(1.5) = —0.076856 < 0
Because a(1.5) and v(1.5) have the same sign, the speed is increasing at time t = 1.5.
2(c) The position of the particle at time t is x(t), and its position at time t = 1 is x(1) = —3. Find the position of the particle at time t = 4. Show the setup for your calculations.
= -3+0.197117 = -2.802883
The position of the particle at time t = 4 is —2.803 (or —2.802 ).
2(d) Find the total distance traveled by the particle over the interval
. Show the setup for your calculations.
= 0.9581
The total distance traveled by the particle over the interval
is 0.958.