Which two quantities have the base unit kg m² s⁻²? A kinetic energy and momentum B kinetic energy and Young modulus C work done and the moment of a couple D work done and pressure - AQA - A-Level Physics - Question 7 - 2022 - Paper 1

Kinetic energy is given by the formula KE = rac{1}{2} mv^2 which has units of kg m² s⁻². Momentum, however, is measured in kg m s⁻¹. Therefore, this pair does not match.

While kinetic energy has the units kg m² s⁻², the Young modulus is given in terms of pressure: ext{Young's modulus} = rac{ ext{Stress}}{ ext{Strain}} which has units of N/m² or kg m⁻¹ s⁻². Thus, this option does not qualify.

Work done is defined as the energy transferred and has the unit kg m² s⁻². The moment of a couple is calculated as force times distance, which also results in units of kg m² s⁻². Therefore, these quantities match the required base unit.

Although work done has the unit kg m² s⁻², pressure is defined as force per area, with units of N/m² or kg m⁻¹ s⁻². This option includes one valid quantity but does not qualify as both match the base unit.