The Physics Behind the Problem

Oct 13, 2025 by wbrum.org 123 views

**Razial's Apple: A Physics Problem**

Understanding the Problem

Razial has just climbed an apple tree so that he is 4.1 m above the ground. He picks a 0.24-kg apple and throws it into the air at a speed of 17.2 m/s. The question is, how fast will it be going just as it reaches the ground?

The Physics Behind the Problem

To solve this problem, we need to understand the concept of conservation of energy. When Razial throws the apple into the air, it gains kinetic energy due to its velocity. As it rises, its kinetic energy is converted into potential energy due to its height. When it reaches its maximum height, all its kinetic energy is converted into potential energy. As it falls back to the ground, its potential energy is converted back into kinetic energy.

The Key to the Solution

The key to this problem is to understand that the total energy of the apple remains constant throughout its motion. This means that the sum of its kinetic energy and potential energy at any point in time is equal to the sum of its kinetic energy and potential energy at any other point in time.

The Math Behind the Solution

Let's break down the math behind the solution:

Initial Kinetic Energy: The initial kinetic energy of the apple is given by the equation:

KE = (1/2)mv^2

where m is the mass of the apple (0.24 kg) and v is its initial velocity (17.2 m/s).

KE = (1/2)(0.24 kg)(17.2 m/s)^2 KE = 14.59 J

Initial Potential Energy: The initial potential energy of the apple is given by the equation:

PE = mgh

where g is the acceleration due to gravity (9.8 m/s^2) and h is the initial height of the apple (4.1 m).

PE = (0.24 kg)(9.8 m/s^2)(4.1 m) PE = 9.83 J

Total Energy: The total energy of the apple is the sum of its kinetic energy and potential energy:

E = KE + PE E = 14.59 J + 9.83 J E = 24.42 J

Final Kinetic Energy: As the apple falls back to the ground, its potential energy is converted back into kinetic energy. The final kinetic energy of the apple is equal to the total energy:

KE = E KE = 24.42 J

Final Velocity: The final velocity of the apple can be found by rearranging the equation for kinetic energy:

v = sqrt(2KE/m) v = sqrt(2(24.42 J)/(0.24 kg)) v = 21.1 m/s

Conclusion

In conclusion, the apple will be going at a speed of 21.1 m/s just as it reaches the ground.

Q&A

Q: What is the initial kinetic energy of the apple? A: The initial kinetic energy of the apple is 14.59 J.

Q: What is the initial potential energy of the apple? A: The initial potential energy of the apple is 9.83 J.

Q: What is the total energy of the apple? A: The total energy of the apple is 24.42 J.

Q: What is the final kinetic energy of the apple? A: The final kinetic energy of the apple is 24.42 J.

Q: What is the final velocity of the apple? A: The final velocity of the apple is 21.1 m/s.

Q: What is the acceleration due to gravity? A: The acceleration due to gravity is 9.8 m/s^2.

Q: What is the mass of the apple? A: The mass of the apple is 0.24 kg.

Q: What is the initial height of the apple? A: The initial height of the apple is 4.1 m.

Q: What is the initial velocity of the apple? A: The initial velocity of the apple is 17.2 m/s.

Q: What is the final velocity of the apple when it reaches the ground? A: The final velocity of the apple when it reaches the ground is 21.1 m/s.