Physics 2006 JAMB Past Questions - Question 18: in an experiment to determine terminal velocity as the pressure incresas the viscosity of a liquid

Correct Answer

C

Explanation

In an experiment to determine terminal velocity as the pressure increases and its effect on the viscosity of a liquid, you would typically follow these steps:

**Materials and Equipment:**
1. A tall and transparent cylindrical container.
2. A liquid with known properties, preferably a viscous one.
3. A small object with known dimensions and weight (e.g., a sphere).
4. A pressure chamber or system to vary pressure.
5. A scale for measuring the weight of the object.
6. Measuring instruments (e.g., rulers, calipers).
7. Stopwatch or timer.
8. Safety equipment (lab coat, gloves, safety goggles).

**Procedure:**

1. **Preparation:**
  a. Ensure the cylindrical container is clean and dry.
  b. Measure and record the dimensions and weight of the object that will be dropped into the liquid.
  c. Measure and record the initial pressure and temperature of the liquid.
  d. Note the properties of the liquid, including density and dynamic viscosity.
  e. Set up the pressure chamber and ensure it is properly calibrated.

2. **Fill the Container:**
  a. Pour the liquid into the cylindrical container, ensuring it is deep enough to allow the object to fall freely for a significant distance.
  b. Record the initial level of the liquid.

3. **Drop the Object:**
  a. Carefully lower the object into the liquid to minimize any initial disturbance.
  b. Make sure the object is released from a consistent height above the liquid's surface.

4. **Measure Terminal Velocity:**
  a. Start the stopwatch as soon as the object is released.
  b. Observe the object as it falls through the liquid. As it approaches terminal velocity, it will reach a constant speed.
  c. Record the time it takes for the object to reach terminal velocity.
  d. Measure the distance it falls during this time.

5. **Calculate Terminal Velocity:**
  a. Use the measured time and distance to calculate the terminal velocity using the formula: V = d/t, where V is the terminal velocity, d is the distance, and t is the time.

6. **Vary Pressure:**
  a. Introduce variations in pressure within the pressure chamber. Record the pressure values as you do this. Make sure to maintain a constant temperature during these pressure changes.

7. **Repeat Steps 3-5:**
  a. Repeat the process of dropping the object into the liquid and measuring terminal velocity for different pressure conditions.

8. **Data Analysis:**
  a. Plot a graph showing terminal velocity (y-axis) as a function of pressure (x-axis).
  b. Analyze the relationship between pressure and terminal velocity to draw conclusions about the effect of pressure on the viscosity of the liquid. Viscosity is indirectly related to terminal velocity in a viscous fluid.

9. **Safety Precautions:**
  a. Wear appropriate safety gear.
  b. Handle the pressure chamber and equipment with care.
  c. Follow safety guidelines for working with chemicals and pressure systems.

10. **Record and Report:**
    Document your experimental setup, data, and findings. Discuss the relationship between pressure and viscosity in your report.

Remember that the relationship between pressure and viscosity in a liquid can be complex, and the above experiment will provide you with data to analyze this relationship. It's important to conduct multiple trials and control for variables that might affect the results.