Use the readings from the rule to find where the centre of the 50 g mass lies on the rule.
Calculate the distance $d$ from the centre of the 50 g mass to the 50.0 cm mark on the rule.
Calculate the value of $\frac{1000}{d}$.
Describe a technique that the student uses to make sure that the value of $d$ is as accurate as possible.
Using the grid in Fig. 3.3, plot a graph of $m$ on the y-axis against $\frac{1000}{d}$ on the x-axis. Draw the straight line of best fit.
Calculate the gradient $G$ of your line. Show all working and indicate on the graph the values you use.
The mass $M$ of the load fixed to the rule can be found from the equation: $M = 22.2 \times G$ Use your value of $G$ from (d)(i) to calculate the mass $M$ of the load fixed to the rule.
Suggest why this method of determining the mass $M$ of the fixed load is unsuitable if a movable load of mass $m = 40\,\text{g}$ is used.