Question

On which body would a 10 kg lamp have the most gravitational potential energy when lifted to height of 2 m? A) Earth B) Mars C) Neptune D) Uranus

Answer 1

Answer:

The correct option is;

C) Neptune

Explanation:

The force of gravity is given by the equation;

$F_g = G\dfrac{m_1m_2}{r^2} = m_2 \times g$

Where:

m₁ = Mass of the planet

m₂ = Mass of the body = 10 kg

r = The distance between the body and the planet = 2 m

g = Gravitational acceleration on the planet

G = Gravitational constant

Given that the potential energy, PE = m × g × h

We have that,

$PE = m_2 \times g \times (r + 2) = G\dfrac{m_1m_2}{r^2} \times (r + 2) \approx G\dfrac{m_1m_2}{r^2} \times r = G\dfrac{m_1m_2}{r}$

Therefore, the gravitational potential energy is directly proportional to the acceleration of gravity, such that the body will have the most gravitational potential energy in the planet with the highest acceleration due to gravity which is Neptune with acceleration due to gravity of 14.07 m/s².

Answer 2

Answer: C.) Neptune

Explanation:

The Gravitational Potential Energy (GPE) of a body is calculated using the formula :

GPE = mgh

Where m = mass of the body

g = acceleration due to gravity

h = distance above a surface

Mass = 10kg

h = 2m

Using the formula :

GPE of lamp on Earth: g = 9.8

GPE = 10 × 9.8 × 2 = 71.8J

GPE of lamp on Mercury: g = 3.59

GPE = 10 × 3.59 × 2 = 196J

GPE of lamp on Mars: g = 3.7

GPE = 10 × 3.7 × 2 = 74J

GPE of lamp on Neptune: g = 14.07

GPE = 10 × 14.07 × 2 = 281.4J

GPE of lamp on Uranus: g = 9

GPE = 10 × 9 × 2 = 180J

GPE of lamp on Pluto: g = 0.42

GPE = 10 × 0.42 × 2 = 8.4J

Neptune has the highest gravitational potential energy as the value of acceleration due to gravity acting on objects is highest on Neptune.