Physics

Problem

1\,\text{kg}

cart is moving due east at

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

. After

0.20\,\text{s}

, it is found to be moving due west at

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

. Determine the magnitude and direction of the average force that acted on the cart during this interval.