Passage II

An object is dropped from a height H above the top of a spring, compressing it. The top of the spring is a distance y below its initial position (see Figure 1) when the spring begins its rebound. At that moment, the object has its maximum upward acceleration, a.

Figure 2 shows, for each of 3 springs—Spring X (the least stiff spring), Spring Y, and Spring Z (the stiffest spring)—a graph of the ratio versus H; g is the acceleration due to gravity.

10. Why, for a given H, is the object’s acceleration greatest when the top of a spring is a distance y meters below its initial position?

Answer and Explanation

Your Answer is

Correct Answer is G

Explanation

First of all, the gravitational acceleration g is a constant, so the H and J options are excluded;

Secondly, when the upward net force received by the object is the largest, the upward acceleration a is also the largest. The elastic force F is upward, and the gravity G is downward, so when F is the largest, the net force is the largest, and a is the largest at this time