If a jogger's velocity begins at 2 m/s and changes to 1.5 m/s uphill, how do you know that the hiker has a negative acceleration

Answer 1

because her speed decreases (has a negative acceleration) by 0.5 m/s.

If the speed goes up it means the object accelerated, if the speed goes down that means there is a negative acceleration

Hpe this helps, ;)