Halley's comet's orbit around the sun is elliptical. When its shortest distance from the sun is = 8.75× 10 100 m, its speed is = 5.46× 104? m？ S- 1, its farthest speed from the sun is = =9.08× 102m? s- 1？ How far is it from the sun at this time? The sun is at the focus of the ellipse. )?

Solution: Halley's comet is attracted by the sun when it orbits the sun-that is, it has the effect of heart force, so the angular momentum is conserved; Because the velocity of Halley's comet at perihelion and apohelion is perpendicular to the orbital radius, there is r 1mv 1=r2mv2.

∴ r2=r 1v 1/v2

Substitute the data to get it.

R2=5.26* 10 to the power of 12.