The small spherical planet called \"Glob\" has a mass of 18 kg and a radius of 5

Question

The small spherical planet called "Glob" has a mass of 18 kg and a radius of 5.69x104 m. An astronaut on the surface of Glob throws a rock straight up. The rock reaches a maximum height of 2.36x103 m, above the surface of the planet, before it falls back down. What was the initial speed of the rock as it left the astronaut's hand? (Glob has no atmosphere, so no energy is ost to air friction.) Tries 0/12 Other Views My general references on what is marked as NEW 1 (EHE7, 8. JIB 2015, 15:02:40 (EDT I'm just lost on this problem. I've tried using (G M/R) but I was getting it wrong. Re: Grant William Levasseur (EtH7 8. JLE 2015, 1 (EDT)) Use the gravitational force equation to find the acceleration due to gravity, then plug that acceleration into v 2-2ax to find the velocity of the object My settings for this discussion 1. B 2. Other Views My general references on what is marked as NEW Send Feedback

Explanation / Answer

Gravitational force, F = GMm/R2 = ma. ...(1)
G is the universal gravitational constant, G = 6.67384 × 10-11 m3 kg-1 s-2
M is the mass of the planet, M = 6.28 x 1018 kg
m is the mass of the object in that planet.
R is the radius of the planet, R = 5.69 x 104 m

From (1), a = GM/R2
= [6.67384 × 10-11 x 6.28 x 1018 ] / [5.69 x 104 ]2. = 0.13 m/s2.

Using Newton's law of motion,
v2 - u2 = 2as
v is the final velocity, v = 0 ( at the highest point)
s is the height reached by the rock, s = 2.36 x 103 m.
a = -0.13 m/s2. (negative because it is deceleration)
substituting,
u = sqrt[2as] = sqrt[ 2 x 0.13 x 2.36 x 103] = 24.77 m/s.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.