A small block with mass 1 kg slides in a vertical circle of radius 0.5 m on the inside of a circular track. There is friction between the trac and the block. At the bottom of the block's path, the speed of the block is 5 m's and at the top of the block's path, the speed of the block 1 m's. In going from the bottom to the top of the track, how much work is done by the friction force on the block?
Simple harmonic motion
Simple harmonic motion is a type of periodic motion in which an object undergoes oscillatory motion. The restoring force exerted by the object exhibiting SHM is proportional to the displacement from the equilibrium position. The force is directed towards the mean position. We see many examples of SHM around us, common ones are the motion of a pendulum, spring and vibration of strings in musical instruments, and so on.
Simple Pendulum
A simple pendulum comprises a heavy mass (called bob) attached to one end of the weightless and flexible string.
Oscillation
In Physics, oscillation means a repetitive motion that happens in a variation with respect to time. There is usually a central value, where the object would be at rest. Additionally, there are two or more positions between which the repetitive motion takes place. In mathematics, oscillations can also be described as vibrations. The most common examples of oscillation that is seen in daily lives include the alternating current (AC) or the motion of a moving pendulum.
![### Understanding Work Done by Friction in a Circular Track
A small block with a mass of 1 kg slides in a vertical circle of radius 0.5 m on the inside of a circular track. There is friction between the track and the block. At the bottom of the block's path, the speed of the block is 5 m/s, and at the top of the block's path, the speed of the block is 1 m/s. The question is: "In going from the bottom to the top of the track, how much work is done by the friction force on the block?"
#### Answer Choices:
- O -11.3 J
- O 10.0 J
- O -9.90 J
- O Cannot be calculated from the given information
- O -2.20 J
#### Detailed Explanation:
To solve this problem, consider the following points:
- **Kinetic Energy at the Bottom:** \( KE_{bottom} = \frac{1}{2} m v^2 = \frac{1}{2} \times 1 \times 5^2 = 12.5 \, \text{J} \)
- **Kinetic Energy at the Top:** \( KE_{top} = \frac{1}{2} m v^2 = \frac{1}{2} \times 1 \times 1^2 = 0.5 \, \text{J} \)
- **Potential Energy at the Bottom:** It's zero since we are taking the bottom as the reference point \( PE_{bottom} = 0 \).
- **Potential Energy at the Top:** \( PE_{top} = mgh = 1 \times 9.8 \times 1 = 9.8 \, \text{J} \) (since the height difference \( h \) is 1 m, the diameter of the circle).
The work-energy principle states that:
\[ W_{\mathrm{friction}} = \Delta KE + \Delta PE \]
Substituting the values:
\[ W_{\mathrm{friction}} = (0.5 - 12.5) + (9.8 - 0) \]
\[ W_{\mathrm{friction}} = -12 + 9.8 \]
\[ W_{\mathrm{friction}} = -2.2 \, \text{J} \]
So, the correct answer is:](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fd955a64d-1d84-4c4c-a975-e65e2fa2eacb%2F5e1bfd29-4ee5-4a34-b46b-94fe6bcdb002%2F4pcodf_processed.jpeg&w=3840&q=75)

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