Math Problem Statement

A particle moves in a straight line. Its displacement, s metres, from a fixed point P at time t seconds is given by s(t) = 3(t + 2)^{\cos t}, for 0 ≤ t ≤ 6.8. Find the particle’s initial displacement from the point P. Find the particle’s velocity when t = 2. Determine the intervals of time when the particle is moving away from the point P.

Solution

Let's tackle each part of this problem step by step.

Part (a): Initial Displacement

The initial displacement occurs at t=0t = 0. Using the function for s(t)s(t): s(0)=3(0+2)cos(0)s(0) = 3(0 + 2)^{\cos(0)} Since cos(0)=1\cos(0) = 1: s(0)=3×21=6meterss(0) = 3 \times 2^1 = 6 \, \text{meters} So, the initial displacement is 6 meters.

Part (b): Velocity at t=2t = 2

The velocity is the derivative of the displacement function s(t)s(t). Let’s differentiate s(t)=3(t+2)costs(t) = 3(t + 2)^{\cos t} with respect to tt using the chain rule and logarithmic differentiation. After finding s(t)s'(t), substitute t=2t = 2 to find the velocity.

Part (c): Intervals of Motion Away from Point P

To find when the particle is moving away from PP, check when s(t)>0s'(t) > 0. This involves analyzing the derivative s(t)s'(t) over the interval 0t6.80 \leq t \leq 6.8 and identifying where it is positive.

Would you like a detailed breakdown of the differentiation process and interval analysis?

Further Questions

  1. How do you determine the direction of particle motion from velocity?
  2. Why is logarithmic differentiation helpful here?
  3. What methods can be used to analyze the intervals of motion?
  4. What role does the cosine function play in determining behavior over time?
  5. How would the initial displacement change if the function's base was altered?

Tip: Use derivative sign analysis to understand motion direction.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Displacement and Velocity
Interval Analysis

Formulas

Displacement function: s(t) = 3(t + 2)^{\cos t}
Velocity as the derivative of displacement: v(t) = s'(t)

Theorems

Chain Rule
Sign Analysis for Motion

Suitable Grade Level

Grades 11-12