Three alternative formulae are suggested for the speed required for a body to escape…
PHYSICS · Multi-part · A Level · Physics · Measurements and their errors · Measurements and their errors
Problem
Three alternative formulae are suggested for the speed ve required for a body to escape from the Earth’s surface:
(1) ve=2gR, (2) ve=gR2, (3) ve=gR
where g is the magnitude of acceleration due to gravity at the surface and R is the radius of the Earth.
(i) Determine the dimensions of each right-hand side.
(ii) Identify the expression(s) whose dimensions match those of speed and hence select the expression that could be correct.