Photo AI
A student carries out an experiment to investigate friction between a puck and the surface of a table - Scottish Highers Physics - Question 2 - 2022
Question 2
A student carries out an experiment to investigate friction between a puck and the surface of a table. The student pushes the puck and releases it at point R. The s... show full transcript
Worked Solution & Example Answer:A student carries out an experiment to investigate friction between a puck and the surface of a table - Scottish Highers Physics - Question 2 - 2022
Step 1
Calculate the average acceleration of the puck between point R and the centre of the target.
Answer
To calculate the average acceleration, we can use the kinematic equation:
where:
- is the final velocity (0 ms⁻¹, as the puck comes to rest),
- is the initial velocity (0.78 ms⁻¹),
- is the acceleration,
- is the distance travelled (2.160 m).
Substituting the known values:
This simplifies to:
Rearranging for :
Thus, the average acceleration is .
Step 2
Calculate the magnitude of the average force of friction between the puck and the table.
Answer
We use Newton's second law to find the force:
where:
- ,
- . (Using the negative sign as the force opposes the motion.)
Substituting in the values:
F = -0.049 \, \text{N}$$ The magnitude of the average force of friction is therefore $0.049 \, \text{N}$.Step 3
Explain why the student's statement is incorrect.
Answer
The student's statement that mass does not have the largest percentage uncertainty is incorrect because mass often has a substantial absolute uncertainty compared to its value. In this case, the mass measurement is with an absolute uncertainty of , leading to a percentage uncertainty of approximately 0.3%. On the other hand, the initial speed is with an absolute uncertainty of , resulting in a percentage uncertainty of about 1.28%, which is larger than that of the mass. Hence, mass does not have the largest percentage uncertainty.