Question
Explain what happens to the potential energy of a rock as it falls off the side of a cliff. The potential energy decreases as the kinetic energy increases. The potential energy decreases as the kinetic energy decreases. The kinetic energy decreases as the potential energy decreases. The kinetic energy decreases as the
Answer
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Martin
Professional · Tutor for 6 years
Answer
To answer this question, we need to understand the concepts of potential energy (PE) and kinetic energy (KE).Potential energy is the energy stored in an object due to its position or configuration. For an object at a height above the ground, its potential energy can be calculated using the formula PE = mgh, where m is the mass of the object, g is the acceleration due to gravity (approximately 9.81 m/s² on Earth), and h is the height above the ground.Kinetic energy is the energy an object possesses due to its motion. The formula for kinetic energy is KE = 1/2 mv², where m is the mass of the object and v is its velocity.Now, let's analyze the situation step by step:Step 1: The rock is initially at rest on the side of a cliff.- At this point, the rock has potential energy due to its height above the ground (PE > 0), and since it is not moving, its kinetic energy is zero (KE = 0).Step 2: The rock begins to fall off the cliff.- As the rock falls, it loses height, so its potential energy decreases because the value of h in the PE = mgh formula is getting smaller.- Simultaneously, as the rock falls, it gains speed, so its kinetic energy increases because the value of v in the KE = 1/2 mv² formula is getting larger.Step 3: The rock continues to fall until it reaches the ground.- Just before the rock hits the ground, its potential energy approaches zero because its height above the ground (h) is nearly zero.- At the same time, its kinetic energy reaches a maximum because its velocity (v) is at its highest just before impact.Therefore, the correct statement regarding what happens to the potential energy of a rock as it falls off the side of a cliff is:The potential energy decreases as the kinetic energy increases.Final Answer: The potential energy decreases as the kinetic energy increases.