Question

Which is an example of negative acceleration?

a snowboarder who increases speed when traveling downhill
a biker who maintains a constant speed through a race
a skateboarder who reduces speed when moving up a hill
a runner who fluctuates speed by increasing and decreasing speed

Answer 1

A skateboarder who reduces speed when moving up a hill.

Explanation: "Negative acceleration" (deceleration) means the speed is decreasing. The skateboarder is slowing down, so their acceleration is opposite their velocity (negative). The biker at constant speed has zero acceleration; the snowboarder increasing speed is positive acceleration; the runner both increases and decreases speed, so sometimes negative but not purely negative.