Deriving the joule
Show that the joule can be expressed as kg m² s⁻².
CIE PRACTICE WORKSHOPReason first.
Reason first.
Then calculate.
Attempt each question on paper. Open the hint only when you are stuck, then compare your method with the complete solution.
Testing a motion equation
A student proposes v = u + 2as. Use dimensions to decide whether it can be correct.
A microscopic capacitance
A capacitor is labelled 47 pF. Express this capacitance in nF and in F.
Density of a cylinder
Mass has 2% uncertainty, diameter 3% and length 1%. Estimate the percentage uncertainty in density ρ = 4m/(πd²l).
Timing oscillations
Explain why timing 20 oscillations gives a more precise period than timing one oscillation.
Resolving a force
A 65 N force acts at 28° above the horizontal. Calculate its horizontal and vertical components.
Equilibrium
Two perpendicular forces are 12 N east and 5 N north. Determine the magnitude and direction of the equilibrant.
Systematic zero error
A micrometer reads +0.04 mm when fully closed. A wire reading is 0.72 mm. State the corrected diameter and explain the effect if no correction is made.