Question

A car moving with an initial velocity of 25m/s north has a constant acceleration of 3m/s2 south. After 6 seconds it’s velocity will be ?

Answer 1

Rectilinear motion uniformly varied (MRUV).

It is that: Occurs on a straight line, with constant acceleration.

Also the same name gives us some clues, the rectiline movement; it is called si because it runs on a straight line and *Uniformly Varied, because the acceleration is constant*, it will never change.

Analyzing what the exercise asks us, which asks us, what will be your speed after 6 seconds?, we understand that it asks us to calculate the final speed.

Data:

• Vo = 25 m/s
• a = 3 m/s²
• t = 6 s
• Vf = ?

We apply the following formula: a = (Vf - Vo)/t

We clear, but here we do it for final velocity, since it is the value we want to calculate.

`\boxed{ \large\displaystyle\text{$\begin{gathered}\sf \bf{V_f=V_o+a*t} \end{gathered}$} }`

To understand the process, we will multiply the acceleration times the time, then add the velocity.

We substitute data in the formula:

`\boxed{\large\displaystyle\text{$\begin{gathered}\sf \bf{V_f=25 \ (m)/(s)+3 \ \frac{m}{\\ot{s^2}}*6 \ s } \end{gathered}$}}`

`\boxed{\large\displaystyle\text{$\begin{gathered}\sf \bf{V_f=25 \ (m)/(s)+18 \ (m)/(s) } \end{gathered}$}}`

`\boxed{\boxed{\large\displaystyle\text{$\begin{gathered}\sf \bf{V_f=43 \ (m)/(s) } \end{gathered}$}}}`

After 6 seconds, its velocity will be 43 m/s.