A skateboarder moves along a straight path

PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Kinematics · Kinematics

Problem

A skateboarder moves along a straight path, taking the forward direction as positive. He starts with velocity

+6\,\text{m/s}

. For the next

2\,\text{s}

he has a uniform acceleration of

+2\,\text{m/s}^2

, followed immediately by

3\,\text{s}

of uniform acceleration of

-4\,\text{m/s}^2

. Answer the following: (i) Find his velocity at the end of the first

2\,\text{s}

. (ii) Find his velocity at the end of the next

3\,\text{s}

. (iii) During which of the two time intervals is he slowing down? Give a reason based on the signs of velocity and acceleration.