Question

the graph below relates velocity to time
the graph would most likely apply to which of the following events?
a soccer ball that is at rest is suddenly kicked.
a ball is thrown upward and returns to the ground.
a person who is running at a constant speed decides to run faster.
a car traveling at a constant speed applies its brakes and comes to a stop.

Explanation:

• For option A: When a soccer ball at rest is suddenly kicked, the velocity - time graph should have an initial velocity of \(0\) and then a sudden increase. But the given graph has a non - zero initial velocity, so this option is incorrect.
• For option B: When a ball is thrown upward and returns to the ground, the velocity first decreases (while going up, decelerating due to gravity), becomes \(0\) at the maximum height, and then increases in the opposite direction (accelerating downwards due to gravity). This does not match the given graph which has a non - zero initial velocity and then a linear decrease to \(0\), so this option is incorrect.
• For option C: If a person is running at a constant speed and then decides to run faster, the velocity should increase. But the given graph shows a decrease in velocity, so this option is incorrect.
• For option D: A car traveling at a constant speed (horizontal part of the graph) and then applying brakes (linear decrease in velocity until it stops, which is when velocity reaches \(0\)) matches the given velocity - time graph.

Answer:

D. A car traveling at a constant speed applies its brakes and comes to a stop.