Westonci.ca is the premier destination for reliable answers to your questions, brought to you by a community of experts. Our platform provides a seamless experience for finding precise answers from a network of experienced professionals. Get precise and detailed answers to your questions from a knowledgeable community of experts on our Q&A platform.

A particle accelerates uniformly from rest at [tex]6 \, \text{ms}^{-2}[/tex] for 8 seconds and then decelerates uniformly to rest in the next 5 seconds. Determine the speed.

A. [tex]9.6 \, \text{ms}^{-1}[/tex]
B. 48


Sagot :

Certainly! Let's break down the problem step-by-step:

1. Initial Acceleration Phase:

- The particle starts from rest, meaning its initial velocity ([tex]\(u\)[/tex]) is 0.
- It accelerates uniformly at [tex]\(6 \, \text{m/s}^2\)[/tex] for [tex]\(8 \, \text{s}\)[/tex].

We need to find the speed at the end of this acceleration phase. We can use the equation of motion:
[tex]\[ v = u + at \][/tex]
where:
- [tex]\(v\)[/tex] is the final velocity
- [tex]\(u\)[/tex] is the initial velocity (0 in this case)
- [tex]\(a\)[/tex] is the acceleration ([tex]\(6 \, \text{m/s}^2\)[/tex])
- [tex]\(t\)[/tex] is the time ([tex]\(8 \, \text{s}\)[/tex])

Substituting the given values:
[tex]\[ v = 0 + (6 \, \text{m/s}^2 \times 8 \, \text{s}) = 48 \, \text{m/s} \][/tex]

Therefore, the speed at the end of the acceleration phase is [tex]\(48 \, \text{m/s}\)[/tex].

2. Deceleration Phase:

- The particle then decelerates uniformly and comes to rest in the next [tex]\(5 \, \text{s}\)[/tex].
- The initial velocity for this phase is the final velocity from the acceleration phase, which is [tex]\(48 \, \text{m/s}\)[/tex].
- The final velocity ([tex]\(v\)[/tex]) at the end of deceleration is [tex]\(0 \, \text{m/s}\)[/tex].

We need to calculate the deceleration ([tex]\(a\)[/tex]).

Using the equation of motion again:
[tex]\[ v = u + at \][/tex]
Given:
- [tex]\(v\)[/tex] is the final velocity (0 \, \text{m/s})
- [tex]\(u\)[/tex] is the initial velocity ([tex]\(48 \, \text{m/s}\)[/tex])
- [tex]\(t\)[/tex] is the time ([tex]\(5 \, \text{s}\)[/tex])

Rearranging the equation to solve for [tex]\(a\)[/tex]:
[tex]\[ 0 = 48 + a \times 5 \][/tex]
[tex]\[ a \times 5 = -48 \][/tex]
[tex]\[ a = - \frac{48}{5} = -9.6 \, \text{m/s}^2 \][/tex]

The negative sign indicates that it is a deceleration.

Thus, the speed after the acceleration phase is [tex]\(48 \, \text{m/s}\)[/tex], and since the particle comes to rest, this also means that it decelerates uniformly over the next [tex]\(5 \, \text{s}\)[/tex].

So, to answer the multiple-choice question:
- The correct answer is B. [tex]\(48 \, \text{m/s}\)[/tex].
Thanks for using our platform. We're always here to provide accurate and up-to-date answers to all your queries. Thanks for stopping by. We strive to provide the best answers for all your questions. See you again soon. Keep exploring Westonci.ca for more insightful answers to your questions. We're here to help.