WAEC Physics 2022 Theory — Question 3
Question 3 of 12 from the West African Examinations Council (WAEC) Physics 2022 Theory paper, with the correct answer and a full explanation.
Advertisement
3. The effective potential energy, E, of a lunar satellite of mass, m₁, moving in an elliptical orbit around the moon of mass, m₂, is given by E=K²/2m₁r² − Gm₁m₂/r, where r is the distance of the satellite from the centre of the moon. Determine the dimensions of the angular momentum, K, of the satellite using dimensional analysis.
Model answer
E = K²/(m₁r²) = Gm₁m₂/r To find the dimensions of K, insert the respective dimensions of G and m: k² = M·L³T⁻²×M×M×L k² = M²L⁴T⁻² Multiply the powers on both sides of the equation by ½: k = M²L⁴T⁻²^(1/2) = ML²T⁻¹ Therefore, dimension of angular momentum = ML²T⁻¹.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.