Math Problem Statement

A particle moving in the [xy]-plane has velocity vector given by [v(t)=\left(10t,6t^{4}\right)] for time [t\geq 0]. At [t=0], the particle is at the point [(-8,-3)]. What is the particle's position at [t=2]?

Solution

To find the particle's position at t=2t = 2, we need to integrate the velocity vector v(t)v(t) to get the position function r(t)r(t).

The velocity vector is given by: v(t)=(10t,6t4)v(t) = \left( 10t, 6t^4 \right)

Step 1: Integrate the velocity components

The position vector r(t)=(x(t),y(t))r(t) = (x(t), y(t)) can be found by integrating each component of the velocity vector.

  • For the x(t)x(t) component: x(t)=10tdt=10tdt=10(t22)+C1=5t2+C1x(t) = \int 10t \, dt = 10 \int t \, dt = 10 \left(\frac{t^2}{2}\right) + C_1 = 5t^2 + C_1

  • For the y(t)y(t) component: y(t)=6t4dt=6t4dt=6(t55)+C2=6t55+C2y(t) = \int 6t^4 \, dt = 6 \int t^4 \, dt = 6 \left(\frac{t^5}{5}\right) + C_2 = \frac{6t^5}{5} + C_2

So, the general position vector is: r(t)=(5t2+C1,6t55+C2)r(t) = \left(5t^2 + C_1, \frac{6t^5}{5} + C_2\right)

Step 2: Determine the constants C1C_1 and C2C_2

We use the initial condition r(0)=(8,3)r(0) = (-8, -3) to find C1C_1 and C2C_2.

  • At t=0t = 0: x(0)=5(0)2+C1=C1=8x(0) = 5(0)^2 + C_1 = C_1 = -8 y(0)=6(0)55+C2=C2=3y(0) = \frac{6(0)^5}{5} + C_2 = C_2 = -3

Thus, C1=8C_1 = -8 and C2=3C_2 = -3.

Step 3: Substitute the constants back into the position function

r(t)=(5t28,6t553)r(t) = \left(5t^2 - 8, \frac{6t^5}{5} - 3\right)

Step 4: Find the position at t=2t = 2

Substitute t=2t = 2 into the position function: x(2)=5(2)28=5(4)8=208=12x(2) = 5(2)^2 - 8 = 5(4) - 8 = 20 - 8 = 12 y(2)=6(2)553=6(32)53=19253=38.43=35.4y(2) = \frac{6(2)^5}{5} - 3 = \frac{6(32)}{5} - 3 = \frac{192}{5} - 3 = 38.4 - 3 = 35.4

Final Answer:

The particle's position at t=2t = 2 is (12,35.4)\boxed{(12, 35.4)}.

Would you like more details on any part of this solution or have any other questions?

Here are some related questions:

  1. What is the velocity of the particle at t=2t = 2?
  2. How do you interpret the velocity vector in terms of direction and magnitude?
  3. What is the total distance traveled by the particle from t=0t = 0 to t=2t = 2?
  4. How would the position change if the initial position were different?
  5. Can you find the acceleration of the particle as a function of time?

Tip: When integrating to find position from velocity, always remember to include the constant of integration, which is determined by the initial conditions.