A-LevelPhysicsDynamics9702/52 · Oct/Nov 2020 · Q115 Marks
A student investigates the motion of a trolley on a wooden surface, as shown in Fig. 1.1. mass m -trolley wooden surface [Figure 1.1] A mass m is placed on the trolley. A mass P is attached to the trolley by string which passes over a pulley. When this mass falls, it pulls the trolley along the surface. The trolley is initially at rest. The student investigates how the speed v of the trolley at a distance d from the initial position of the trolley varies with m. It is suggested that the relationship between v and m is 2d/v² = (m+R) / (Pg-Q) where g is the acceleration of free fall and Q and R are constants. Design a laboratory experiment to test the relationship between m and v. Explain how your results could be used to determine values for Q and R. You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to: • the procedure to be followed • the measurements to be taken • the control of variables • the analysis of the data • any safety precautions to be taken.
- A student investigates the motion of a trolley on a wooden surface, as shown in Fig. 1.1. mass m -trolley wooden surface [Figure 1.1] A mass m is placed on the trolley. A mass P is attached to the trolley by string which passes over a pulley. When this mass falls, it pulls the trolley along the surface. The trolley is initially at rest. The student investigates how the speed v of the trolley at a distance d from the initial position of the trolley varies with m. It is suggested that the relationship between v and m is 2d/v² = (m+R) / (Pg-Q) where g is the acceleration of free fall and Q and R are constants. Design a laboratory experiment to test the relationship between m and v. Explain how your results could be used to determine values for Q and R. You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to: • the procedure to be followed • the measurements to be taken • the control of variables • the analysis of the data • any safety precautions to be taken.[15]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2020). The mark or mark type is shown in brackets.
- [1] m is the independent variable and v is the dependent variable or vary m and measure v
- [1] keep P constant
- [1] labelled diagram of workable experiment including: • P attached to string • string passing over a supported pulley • string horizontally attached to trolley • labels for pulley and P
- [1] method to determine v e.g. • light gate attached to a timer to measure v • motion sensor connected to data logger • ticker tape timer • measure d, and t with timer/stopwatch/light gate and timer (to calculate v)
- [1] use a (top pan) balance to measure m
- [1] measure d with a ruler
- [1] plot a graph of 1 / v² against m or m against 1 / v²
- [1] Q = Pg / (2d x gradient) or Q = Pg - (gradient / 2d) (consistent with graph)
- [1] R = 2d ×(Pg – Q)×y-intercept (= y-intercept / gradient ) or R = -y-intercept (consistent with graph)
- [1] D1 safety precaution related to falling mass P or preventing trolley falling e.g. cushion/sandbox for P, barrier for trolley
- [1] D2 keep d constant
- [1] D3 use a large distance for d
- [1] D4 method to keep d constant, e.g. mark starting and end positions
- [1] D5 v = distance / time for appropriate small distance on ticker tape/card/distance between light gates (not d) or use of v = 2d / t if d and total time measured
- [1] D6 method to ensure wooden surface is horizontal, e.g. spirit level
- [1] D7 for same m repeat experiment to find average v or t
- [1] D8 1/v² = m/(2d×(Pg-Q)) + R/(2d×(Pg – Q)) or m = 2d(Pg-Q)/V² - R (consistent with graph)
- [1] D9 relationship valid if a straight line (not passing through the origin)
- [1] D10 method of attaching mass m to trolley e.g. tape, adhesive putty
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →