Question

A buzzard is flying 98m above the Earth's surface. Assuming g = 9.8N/kg, what is the mass of the buzzard if the gravitational potential energy stored is 5,403J?​

Answer 1

Approximately
`5.6\; {\rm kg}`.

Step-by-step explanation:

In a uniform gravitational field, the gravitational potential energy
`(\text{GPE})` of an object can be found with the following equation:

`(\text{GPE}) = m\,g \, h`,

Where:

• 
  `m` is the mass of this object,
• 
  `g` is the gravitational field strength, and
• 
  `h` is the height of the object above a given surface where
  `(\text{GPE})` is
  `0` (e.g., the ground.)

In this question, it is given that
`g = 9.8\; {\rm N\cdot kg^(-1)}` and
`h = 98\; {\rm m}`. Rearrange the expression for
`(\text{GPE})` to find
`m`:

`\begin{aligned}m &= \frac{(\text{GPE})}{g\, h} \\ &= (5403)/((9.8)\, (98))\; {\rm kg} \\ &\approx 5.6\; {\rm kg}\end{aligned}`.

In other words, the mass of this object would be approximately
`5.6\; {\rm kg}`.