A student is performing an experiment to determine the density of the material of a metre rule.
The student sets up a balancing experiment to find the mass of the rule, where a pivot is placed between the 50.0 cm50.0\text{ cm}50.0 cm mark of the rule and an added load XXX of mass k=150 gk = 150\text{ g}k=150 g placed near one end.
On the laboratory diagram, which is drawn to a scale of 1:5 (one-fifth of the actual size):
(i) Calculate the actual distance xxx (in cm\text{cm}cm) from the centre of the load XXX to the pivot. (ii) Calculate the actual distance yyy (in cm\text{cm}cm) from the pivot to the 50.0 cm50.0\text{ cm}50.0 cm mark on the rule. (iii) Calculate the mass mmm (in g\text{g}g) of the metre rule using the equation:
m=kxy m = \frac{kx}{y} m=ykxThe average width of the metre rule is measured as w=2.80 cmw = 2.80\text{ cm}w=2.80 cm and average thickness is measured as t=0.50 cmt = 0.50\text{ cm}t=0.50 cm. (i) Calculate the volume VVV (in cm3\text{cm}^3cm3) of the metre rule using the equation V=lwtV = lwtV=lwt, where the actual length of the metre rule is l=100.0 cml = 100.0\text{ cm}l=100.0 cm. (ii) Calculate the density ρ\rhoρ of the metre rule using the equation ρ=mV\rho = \frac{m}{V}ρ=Vm. State your answer to 3 significant figures and include the appropriate unit.
State the assumption that the student has made about the position of the centre of mass of the metre rule.
169 exam-style questions on CIE IGCSE Physics Density, covering Density. Each one has a worked solution and a mark scheme showing where the marks go.