Chapter 2.3, Problem 26R

To determine

the change in velocity of a car that starts at rest.

Answer to Problem 26R

The change in velocity is $\boxed{\Delta v=20\text{m/s}}$ .

Explanation of Solution

Given:

Final velocity of the ball is $v=20\text{m/s}$ .

Initial velocity is $u=0\text{m/s}$ .

Formula used:

The change in velocity is the difference in initial and final velocity of the car along the same direction.

The change in velocity is

  $\Delta v=v-u$....................(1)

Here, $v$ and $u$ are final and initial velocity.

Calculation:

Substitute $0\text{m/s}$ for $u$ , and $20\text{m/s}$ for $v$ in equation (1)

  $\begin{array}{l}\Delta v=20\text{m/s}-0\text{m/s}\\ \boxed{\Delta v=20\text{m/s}}\end{array}$

Conclusion:

Hence, the change in velocity is $\boxed{\Delta v=20\text{m/s}}$ .