Physics

Problem

A skateboard of mass

4\,\text{kg}

is moving forward at

1\,\text{m\,s}^{-1}

. A horizontal force of

12\,\text{N}

acts in the direction of motion for the next

3\,\text{s}

. Immediately afterwards, only a frictional force of

4\,\text{N}

acts opposite to the motion for

2\,\text{s}

. What is the speed of the skateboard at the end of the

5\,\text{s}

interval? a)

10\,\text{m/s}

forward b)

8\,\text{m/s}

forward c)

6\,\text{m/s}

forward d)

12\,\text{m/s}

forward