Home / AP Calculus AB : 4.2 Straight-Line Motion: Connecting Position, Velocity, and Acceleration- Exam Style questions with Answer- FRQ

AP Calculus AB : 4.2 Straight-Line Motion: Connecting Position, Velocity, and Acceleration- Exam Style questions with Answer- FRQ

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

(t24t+5)0.2t.

 

(a) There is one time, 

t=tR

, in the interval 0 <  t < 2 when the particle is at rest (not moving). Find 

tR

. For  0 < t < 

tR

, 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 

1t4

. Show the setup for your calculations.

▶️Answer/Explanation

Ans:

2(a) There is one time, t = 

tR

, in the interval 0 < 7 < 2 when the particle is at rest (not moving). Find 

tR

.For 0 <t < 

tR

, 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 

tR

, = 1.426 (or 1.425).

For 

0<t<tR,v(t)>0

. 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.

x(4)=x(1)+14v(t)dt

= -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 

1t4

. Show the setup for your calculations.

14|v(t)|dt

= 0.9581

The total distance traveled by the particle over the interval 

1t4

 

is 0.958.

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