PHY
posted by abc .
Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2.
(a) Use these numbers to calculate the escape speed from the surface of Eris.
1360 m/s correct answer.
(b) If an object is fired directly upward from the surface of Eris with one third of this escape speed, to what maximum height above the surface will the object rise? (Assume that Eris has no atmosphere and negligible rotation.)

PE at the surface: GMm/r but you are given
g=Force/mass=GM/r^2 =.77
PE at Surface then=GMm/r*r/r=mgr
escape velocity for KE=PE
1/2 mV^2=mgr
Vescape= sqrt (2gr)
checking book answer Vesc=sqrt(2*.77*1.2E6)=text answer.
Respond to this Question
Similar Questions

Physics
A 21.0kg satellite has a circular orbit with a period of 2.37 h and a radius of 8.50×106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 7.10 m/s2, what is the … 
PhysicsGravity
A 17.0kg satellite has a circular orbit with a period of 2.31 h and a radius of 9.10×106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 8.10 m/s2, what is the … 
physics
On a distant planet, the acceleration due to gravity is 5.30 m/s2, and the radius is 4600 km. Use the law of gravitation to calculate the mass of this planet. 
physics
An object rests on the surface of planet y. Its mass is unknown. Find the acceleration due to gravity near the surface of planet y. Answer in m/s/s. G=6.673x10^23 radius of planet y=2439700m mass of planet y=3.302x10^23kg radius of … 
physics
Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2. (a) Use these numbers to calculate the escape speed from the surface of … 
Physics
Gravity on Titan Titan is the largest moon of Saturn and the only moon in the solar system known to have a substantial atmosphere. Find the acceleration due to gravity on Titan's surface, given that its mass is 1.35 X 10^23 kg and … 
Physics
Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2. (a) Use these numbers to calculate the escape speed from the surface of … 
Physics
Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2. (a) Use these numbers to calculate the escape speed from the surface of … 
College Physics
Suppose a planet is discovered that has the same total mass as the Earth, but half its radius. Calculate the acceleration due to gravity on the surface of this planet. 
physics
An astronaut is on the surface of planet whose air resistance is negligible. To measure the acceleration due to gravity(g) he throws a stone upwards. He observe that the stone reaches the surface to a maximum ht of h =10m(which is …