(d) The particle moves in the positive direction when its velocity has a positive sign. You know the particle is at rest when $t=0$ and $t=3$ , and because the velocity function is continuous, you need only check the sign of $v(t)$ for values on the intervals (0, 3) and (3, 6).

We have, for instance $v(1)\approx-0.91$ and $v(4)\approx0.91>0$ , which means the particle is moving the positive direction for $3$ , or the interval (3, 6).

(e) The total distance traveled is obtained by integrating the absolute value of the velocity function over the given interval:

$\displaystyle\int_0^6|v(t)|\,\mathrm dt=\int_0^3-v(t)\,\mathrm dt+\int_3^6v(t)\,\mathrm dt$

which follows from the definition of absolute value. In particular, if $x$ is negative, then $|x|=-x$ .

The total distance traveled is then 4 ft.

(g) Acceleration is the rate of change of velocity, so $a(t)$ is the derivative of $v(t)$ :

$a(t)=v'(t)=-\dfrac{\pi^2}9\cos\left(\dfrac{\pi t}3\right)$

Compute the acceleration at $t=4$ seconds:

$a(t)=\dfrac{\pi^2}{18}\dfrac{\rm ft}{\mathrm s^2}$

(In case you need to know, for part (i), the particle is speeding up when the acceleration is positive. So this is done the same way as part (d).)

6 0

3 years ago

A container shaped as a rectangular prism can hold 840 wooden cube blocks with edge lengths of

asambeis [7]

First, fidn the volume of the little cubes that the rectangular prism can hold instide of itself. The formula for volume is length x width x height. This means you have to multiply 1/2 x 1/2 x 1/2. 1/2 x 1/2 x 1/2 = 1/8. Now, since the rectangular prism can hold 840 of these cubes, you need to multiply each cube's volume, 1/8, by 840. 1/8 x 840 = 105.

Your answer should be: 105 ft.^3

4 0

3 years ago

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It was noted that the probability of a flight arriving early is 1/10 and the probability of a flight arriving late is 2/5

Aloiza [94]

Assuming independence,
prob=P(late,early)+P(early,late)=(1/10)(2/5)+(2/5)(1/10)

8 0

3 years ago