Question

the graph of position vs. time for an object moving along a straight line is given. during the time shown on the graph, the speed and net force on the object will have which of the following characteristics?
a speed increasing, net force zero
b speed increasing, net force constant but not zero
c speed constant but not zero, net force constant but not zero
d speed constant but not zero, net force zero

Explanation:

1. Analyze the position - time graph: The graph is a straight line, which means the slope (representing velocity, and speed is the magnitude of velocity) is constant. So the speed is constant and not zero (since the slope is non - zero).
2. Recall Newton's first law: If an object is moving with a constant velocity (constant speed in a straight line), the net force acting on it is zero. So we need to find the option where speed is constant (non - zero) and net force is zero.

• Option A: Says speed is increasing, which is wrong as the slope is constant.
• Option B: Says speed is increasing, wrong.
• Option C: Says net force is constant but not zero, wrong. If net force is non - zero, acceleration is non - zero (by \(F = ma\)) and speed would change.
• Option D: Speed is constant (non - zero) and net force is zero, which matches our analysis.

Answer:

D. Speed constant but not zero, Net Force Zero