Difficulty: Medium

Average Score: 73%

Salt water causes marine ecosystems to be very different from freshwater ecosystems. Organisms in both types of ecosystems are affected by the freezing and melting of ice. An experiment was conducted to test the hypothesis that ice melts faster in salt water than in fresh water. Ice cubes made of fresh water were placed into cups containing either fresh water or salt water. Various data were recorded, and the energy released by each melting ice cube was calculated from the data. The table shows the results for each cup.

Two people are standing at the edge of a high cliff. One person throws a rock horizontally off the cliff. Which uncontrolled part of this investigation can prevent the rocks from hitting the ground at the same time?

Rationale

Air resistance can prevent the rocks from hitting the ground at the same time.

Air resistance acts differently on objects as they fall, particularly when they are thrown horizontally. This force can vary based on the shape and speed of the rocks, impacting their descent time despite being released simultaneously.

A (gravity) YOUR ANSWER

Gravity is a constant force that acts on both rocks equally, pulling them downward with the same acceleration. Since gravity affects all objects in free fall uniformly, it will not differentiate between the two rocks, ensuring they both experience the same gravitational pull.

B (mass of the rocks) YOUR ANSWER

The mass of the rocks does not influence their fall time when only gravity is acting on them in a vacuum. Both rocks will fall to the ground at the same rate regardless of their mass, as demonstrated by Galileo's experiments. In the presence of air, while mass can affect air resistance, it does not determine the time it takes to hit the ground.

D (strength of the person) YOUR ANSWER

The strength of the person throwing the rock does not impact the time it takes for the rocks to reach the ground. While a stronger throw may affect the initial horizontal velocity, both rocks will still be subjected to the same forces of gravity and air resistance during their fall.

Conclusion

In this investigation, the uncontrolled variable that can cause the two rocks to hit the ground at different times is air resistance. While gravity acts uniformly on both rocks, factors like their shape and the speed at which they are thrown will influence how air resistance affects their fall. Understanding these dynamics is crucial in physics experiments involving projectile motion.

Two people are standing at the edge of a high cliff. One person throws a rock horizontally off the cliff. Which uncontrolled part of this investigation can prevent the rocks from hitting the ground at the same time?

Air resistance can prevent the rocks from hitting the ground at the same time.

Related Questions

Related Quizzes

How familiar were you with this question?

Report an Issue

Rate this Practice Test