Chapter SH, Problem 3.9APP

To determine

To Calculate: The net force on car.

Answer to Problem 3.9APP

6000 N

Explanation of Solution

Given:

Initial velocity of car, $u=15\text{m/s}$

Final velocity of car, $v=30\text{m/s}$

Time elapsed, $t=10.0\text{s}$

Mass of the car, $m=4000\text{kg}$

Formula Used:

The acceleration of the cart can be obtained by using the first equation of motion:

  $a=\frac{v-u}{t}$

Here, v is the final velocity, u is the initial velocity and tis time.

From Newton’s second law of motion, the net force would be:

  ${\displaystyle \sum F=ma}$

Here, m is the mass and a is the acceleration.

Calculations:

Substitute the values and solve:

  $\begin{array}{l}a=\frac{v-u}{t}\\ a=\frac{30-15}{10}\\ a=1.5{\text{m/s}}^{\text{2}}\end{array}$

  $\begin{array}{l}F=ma\\ F=\left(4000\text{kg}\right)\left(\text{1}\text{.5}{\text{m/s}}^{\text{2}}\right)\\ F=6000\text{N}\end{array}$

Conclusion:

Thus, the net force on car is 6000 N.