Physics with Calc - Please use the appropriate units and round to the .000 if ne
ID: 1409047 • Letter: P
Question
Physics with Calc - Please use the appropriate units and round to the .000 if needed.
A comet moves about the Sun in an elliptical orbit, with its closest approach to the Sun being about 0.605 AU and its greatest distance from the sun being 29.0 AU (1 AU = the Earth-Sun distance). If the comet's speed at closest approach is 54.0 km/s, what is its speed when it is farthest from the Sun? (The gravitational force exerted by the Sun on the comet is parallel to the moment arm, so exerts no torque. Therefore, angular momentum of the comet around the Sun is conserved.)
Explanation / Answer
Given :-
Vclosed = 54 km/sec
Rclosed = 0.605 A.U
Rfar = 29 A.U
from coservation of angular momentum
Lclose = Lfar
(MVR)close = (MVR)far
Since the problem neglected any change in the comet's mass, we can focus on the velocity and radius
(VR)close = (VR)far
Vfar = Vclose(Rclose / Rfar)
Vfar = 54 km/sec*(0.605 A.U / 29 A.U)
Vfar = 1.127 km/sec