Chapter 3.2, Problem 17PP

To determine

To Calculate: The velocity of the bus after $6.8\text{ s}.$

Answer to Problem 17PP

  $18.54\text{m/s}$

Explanation of Solution

Given:

The bus is travelling at an initial velocity of $30.0\text{ km/h}$ east, and it has a constant acceleration $1.5{\text{m/s}}^{\text{2}}$ .

Formula used:

Final velocity with constant acceleration is given by

  $v_{final}=v_{initial}+a\Delta t$

Where, $\Delta t$ is the time taken, v indicates velocity and a is the acceleration.

Calculation:

Using the given values of initial velocity, acceleration, and the time taken in above formula, the final velocity after $6.8\text{ s}$ is:

  $\begin{array}{c}{v}_{final}=v_{initial}+a\Delta t\\ =\left(30\times \frac{1000}{3600}\right)\text{m/s}+\left(1.5\times 6.8\right)\\ =8.34\text{m/s}+10.2\text{m/s}\\ =18.54\text{m/s}\end{array}$

Conclusion:

Thus, the final velocity of the bus after $6.8\text{ s}$ is $18.54\text{m/s}$ .