Question

1 quincy is monitoring the movement of a particle along the ( x )-axis of an ( x y ) plane. the velocity is negative, and the acceleration is positive. which of the following describes what quincy observes?
the particle is moving in the positive direction, and its speed is decreasing
the particle is moving in the negative direction, and its speed is decreasing
the particle is moving in the positive direction, and its speed is increasing
the particle is moving in the negative direction, and its speed is increasing

Explanation:

Step1: Analyze the direction of motion

Velocity is a vector quantity. A negative velocity means the particle is moving in the negative direction.

Step2: Analyze the effect of acceleration on speed

Acceleration is the rate of change of velocity. If acceleration \(a\) and velocity \(v\) have opposite signs (\(a>0\), \(v < 0\)), the magnitude of the velocity (speed) is decreasing. For example, if \(v=-t\) (where \(t\) is time) and \(a = 1\), \(v\) is getting closer to \(0\) as \(t\) increases.

Answer:

The particle is moving in the negative direction, and its speed is decreasing.