This questions was popular among the candidates and its was fairly well attempted. However, some candidates that attempted this question were unable to determine me, Q mean, T and T2. Some recorded their values to wrong number of decimal places. Few candidates calculated T as n/t instead of t/n. Some candidates also experiences difficulty in presenting a complete and composite table for the data. This led to poor plotting of the resulting graphs and stating of acceptable precautions.
Part (b) of this question was poorly rendered as few of the candidates recalled correctly the three forces acting on the test-tube in the water while majority mentioned only two of the forces. Many of the candidates also failed to recognize fluid friction (viscosity) as the force responsible for the gradual decrease in the amplitude of oscillation of the loaded test-tube with time in water.
The expected answers are:
- Candidates are expected to read and record five values of the following variables and quantities to the required number of decimal places and tolerance:
Ms , d, me , t , T, T2 and L
- Read and record Qmean
- Plot five points on graph using reasonable scales on correctly distinguish axes.
- Draw line of best fit
- Determine the slope of the graph using large right-angled triangle
- Determination of the intercept c on the vertical axis
- Evaluation of k = 4π2s/Q
- State any two of the following precautions
e.g
- Avoided parallax error in reading clock / weighing balance / metre rule
- Zero error noted and corrected on metre rule / clock/weighing balance
- Repeated readings stated
- Dry/clean test tube before weighing
- Avoid draught or wind
The expected answers to part (b) are:
- Weight, upthrust and viscous force / drag or liquid friction.
- The amplitude of oscillation of a loaded test tube decreases with time because of the viscous drag (force) which opposes the motion
OR
Because of damping effect due to viscous drag (liquid friction)This questions was popular among the candidates and its was fairly well attempted. However, some candidates that attempted this question were unable to determine me, Q mean, T and T2. Some recorded their values to wrong number of decimal places. Few candidates calculated T as n/t instead of t/n. Some candidates also experiences difficulty in presenting a complete and composite table for the data. This led to poor plotting of the resulting graphs and stating of acceptable precautions.
Part (b) of this question was poorly rendered as few of the candidates recalled correctly the three forces acting on the test-tube in the water while majority mentioned only two of the forces. Many of the candidates also failed to recognize fluid friction (viscosity) as the force responsible for the gradual decrease in the amplitude of oscillation of the loaded test-tube with time in water.
The expected answers are:
- Candidates are expected to read and record five values of the following variables and quantities to the required number of decimal places and tolerance:
Ms , d, me , t , T, T2 and L
- Read and record Qmean
- Plot five points on graph using reasonable scales on correctly distinguish axes.
- Draw line of best fit
- Determine the slope of the graph using large right-angled triangle
- Determination of the intercept c on the vertical axis
- Evaluation of k = 4π2s/Q
- State any two of the following precautions
e.g
- Avoided parallax error in reading clock / weighing balance / metre rule
- Zero error noted and corrected on metre rule / clock/weighing balance
- Repeated readings stated
- Dry/clean test tube before weighing
- Avoid draught or wind
The expected answers to part (b) are:
- Weight, upthrust and viscous force / drag or liquid friction.
- The amplitude of oscillation of a loaded test tube decreases with time because of the viscous drag (force) which opposes the motion
OR
Because of damping effect due to viscous drag (liquid friction)